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  • 1.
    Alexandersson, Martin
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Chalmers University of Technology, Sweden.
    Kjellberg, Martin
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Mao, W.
    Chalmers University of Technology, Sweden.
    Ringsberg, Jonas W
    Chalmers University of Technology, Sweden.
    Prediction of roll motion using fully nonlinear potential flow and ikeda’s method2021Ingår i: Proceedings of the International Offshore and Polar Engineering Conference, International Society of Offshore and Polar Engineers , 2021, s. 1670-1679Konferensbidrag (Refereegranskat)
    Abstract [en]

    Getting the best possible accuracy with the lowest possible computational cost is an important factor in the early design stage of ships. Potential flow-based analysis presents such a solution for seakeeping analyses. The accuracy of roll motion in potential flow is however not so good, due to the large influence from vicsous roll damping, which is missing in these calculations. This paper proposes a hybrid method, as a solution to this problem, where the viscous roll damping from Ikeda’s semi-empirical method is injected into an existing 3D unsteady fully nonlinear potential flow (FNPF) method. The hybrid method is investigated using roll decay tests with the KVLCC2 test case. This investigation shows that the accuracy of simulated roll motions is significantly improved and also shows good agreement with the corresponding roll decay model tests.

  • 2.
    Alexandersson, Martin
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Chalmers University of Technology, Sweden.
    Mao, Wengang
    Chalmers University of Technology, Sweden.
    Ringsberg, Jonas W
    Chalmers University of Technology, Sweden.
    Analysis of roll damping model scale data2021Ingår i: Ships and Offshore Structures, ISSN 1744-5302, E-ISSN 1754-212X, Vol. 16, nr S1, s. 85-92Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Having an accurate prediction of ship roll damping is crucial when analysing roll motions. In this paper, the simplified Ikeda method (SI-method) is compared with the original Ikeda method. The methods are compared using results from a database of roll decay tests carried out on modern merchant ships and a smaller set of predictions in which the original Ikeda method was used. It was found that most of the ships in the database had dimensions outside the limits of the SI-method. Thus, the SI-method showed poor agreement with model tests outside its limits but acceptable agreement for ships within limits. It was found that the deviations were caused by extrapolation errors of the wave-damping in the SI-method. Two ways to improve the accuracy of the SI-method were proposed based on regression, which gave about the same accuracy as the original Ikeda method. © 2021 The Author(s).

  • 3.
    Alexandersson, Martin
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Chalmers University of Technology, Sweden.
    Mao, Wengang
    Chalmers University of Technology, Sweden.
    Ringsberg, Jonas W
    Chalmers University of Technology, Sweden.
    System identification of Vessel Manoeuvring Models2022Ingår i: Ocean Engineering, ISSN 0029-8018, E-ISSN 1873-5258, Vol. 266, artikel-id 112940Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Identifying the ship's maneuvering dynamics can build models for ship maneuverability predictions with a wide range of useful applications. A majority of the publications in this field are based on simulated data. In this paper model test data is used. The identification process can be decomposed into finding a suitable manoeuvring model for the hydrodynamic forces and to correctly handle errors from the measurement noise. A parameter estimation is proposed to identify the hydrodynamic derivatives. The most suitable manoeuvring model is found using the parameter estimation with cross-validation on a set of competing manoeuvring models. The parameter estimation uses inverse dynamics regression and Extended Kalman filter (EKF) with a Rauch Tung Striebel (RTS) smoother. Two case study vessels, wPCC and KVLCC2, with very different maneuverability characteristics are used to demonstrate and validate the proposed method. Turning circle predictions with the robust manoeuvring models, trained on zigzag model tests, show good agreement with the corresponding model test results for both ships. © 2022 The Author(s)

  • 4.
    Alexandersson, Martin
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Chalmers University of Technology, Sweden.
    Zhang, Daiyong
    Chalmers University of Technology, Sweden.
    Mao, Wengang
    Chalmers University of Technology, Sweden.
    Ringsberg, Jonas W
    Chalmers University of Technology, Sweden.
    A comparison of ship manoeuvrability models to approximate ship navigation trajectories2023Ingår i: Ships and Offshore Structures, ISSN 1744-5302, E-ISSN 1754-212X, Vol. 18, nr 4, s. 550-557Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is essential to describe a ship’s manoeuvrability for various applications, e.g. optimal control of unmanned surface vehicles (USVs). In this study, the capability of two recognised manoeuvrability models to predict ships’ trajectories is investigated based on both simulation and open-water experiment test data. The parameters of these models are estimated by a statistical learning method. The goodness of the two estimated models for describing a merchant ship’s manoeuvrability is first studied using her manoeuvring simulation data. Then, experimental manoeuvring tests to use a USV in open water with wind and drifting effects are used to check the conventional model identification procedures. Finally, some modifications and adjustments are proposed to improve the conventional procedures. It shows that the proposed procedures can accurately derive the ship’s manoeuvrability based on experimental data. © 2022 The Author(s). 

  • 5.
    Altuntas Vural, Ceren
    et al.
    Chalmers University of Technology, Sweden.
    Gonzalez-Aregall, Marta
    University of Gothenburg, Sweden.
    Woxenius, Johan
    University of Gothenburg, Sweden.
    Rogerson, Sara
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Svanberg, Martin
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    International container shipping through the Covid-19 pandemic - Disruptions from a Swedish perspective2024Rapport (Övrigt vetenskapligt)
    Abstract [en]

    At the onset of the pandemic in spring 2020, the Swedish shipping sector was first affected by border closures preventing passengers to use RoPax shipping and cruise ferries. There were some blank sailings but in general they kept operating to foster intra-European trade by trucks despite the missing revenues from passengers. Shipping in general was affected by port disrup-tions and complicated crew changes. Eventually, however, it was clear that the most dramatic disruptions on a global scale where experienced in the container segment. General media reported on delayed goods, high freight rates and, however not related to the pandemic, the Ever Given blocking the Suez Canal for a week in March 2021. Currently, there are few reports of supply chains and shipping suffering from disruptions and capacity constraints related to the pandemic. The peak in freight rates was rather replaced by depressed rates and there is a certain risk that some logisticians and supply chain managers regard the pandemic as a once-in-a-lifetime event and just want to get back to a previous be-haviour seeing container shipping as a commodity with indefinite capacity at a reasonable price. Nevertheless, the war in Ukraine, the drought in the Panama Canal and the attacks by the Houthi rebels in the Red Sea create other problems for container shipping. Freight rates increase significantly, but from very low levels. The purpose of the report is to describe and analyse how international container shipping was affected by the Covid-19 pandemic and other disruptions. The analysis takes a Swedish perspective on disruptions and tries to go beyond the anecdotal reporting and capture what happened and why. Container shipping is put into a context of economy, consumption, world trade, supply chains and logistics. The pandemic and more current events affecting container shipping market are described together with how shipping lines responded. A series of interviews with Swedish actors revealed how they perceived the disruptions and what countermeasures the actors have applied to mitigate the effects, their organisational learning and how they prepare for future disruptions

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  • 6.
    Andersson, Jennie
    et al.
    Chalmers University of Technology, Sweden.
    Shiri, Alex
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Bensow, Rickard
    Chalmers University of Technology, Sweden.
    Yixing, Jin
    China Ship Scientific Research Center, China.
    Chengsheng, Wu
    China Ship Scientific Research Center, China.
    Gengyao, Qiu
    China Ship Scientific Research Center, China.
    Deng, Ganbo
    Ecole Centrale de Nantes, France.
    Queutey, Patrick
    Ecole Centrale de Nantes, France.
    Xing-Kaeding, Yan
    Hamburg Ship Model Basin, Germany.
    Horn, Peter
    Hamburg Ship Model Basin, Germany.
    Lücke, Thomas
    Hamburg Ship Model Basin, Germany.
    Kobayashi, Hiroshi
    National Maritime Research Institute, Japan.
    Ohashi, Kunihide
    National Maritime Research Institute, Japan.
    Sakamoto, Nobuaki
    National Maritime Research Institute, Japan.
    Yang, Fan
    Shanghai Ship and Shipping Research Institute, Chia.
    Gao, Yuling
    Shanghai Ship and Shipping Research Institute, China.
    Windén, Björn
    SHORTCUt CFD, USA.
    Meyerson, Max
    University of Michigan, USA.
    Maki, Kevin
    University of Michigan, USA.
    Turnock, Stephen
    University of Southampton, UK.
    Hudson, Dominic
    University of Southampton, UK.
    Banks, Joseph
    University of Southampton, UK.
    Terziev, Momchil
    University of Strathclyde, UK.
    Tezdogan, Tahsin
    University of Strathclyde, UK.
    Vesting, Florian
    Volupe AB, Sweden.
    Hino, Takanori
    Yokohama National University, Japan.
    Werner, Sofia
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Ship-scale CFD benchmark study of a pre-swirl duct on KVLCC22022Ingår i: Applied Ocean Research, ISSN 0141-1187, E-ISSN 1879-1549, Vol. 123, artikel-id 103134Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Installing an energy saving device such as a pre-swirl duct (PSD) is a major investment for a ship owner and prior to an order a reliable prediction of the energy savings is required. Currently there is no standard for how such a prediction is to be carried out, possible alternatives are both model-scale tests in towing tanks with associated scaling procedures, as well as methods based on computational fluid dynamics (CFD). This paper summarizes a CFD benchmark study comparing industrial state-of-the-art ship-scale CFD predictions of the power reduction through installation of a PSD, where the objective was to both obtain an indication on the reliability in this kind of prediction and to gain insight into how the computational procedure affects the results. It is a blind study, the KVLCC2, which the PSD is mounted on, has never been built and hence there is no ship-scale data available. The 10 participants conducted in total 22 different predictions of the power reduction with respect to a baseline case without PSD. The predicted power reductions are both positive and negative, on average 0.4%, with a standard deviation of 1.6%-units, when not considering two predictions based on model-scale CFD and two outliers associated with large uncertainties in the results. Among the variations present in computational procedure, two were found to significantly influence the predictions. First, a geometrically resolved propeller model applying sliding mesh interfaces is in average predicting a higher power reduction with the PSD compared to simplified propeller models. The second factor with notable influence on the power reduction prediction is the wake field prediction, which, besides numerical configuration, is affected by how hull roughness is considered. © 2022 The Authors

  • 7.
    Awais, Fawad
    et al.
    University of Gothenburg, Sweden.
    Flodén, Jonas
    University of Gothenburg, Sweden.
    Svanberg, Martin
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Logistic characteristics and requirements of Swedish wood biofuel heating plants2021Ingår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 138, artikel-id 110650Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The demand for wood biofuel for district heating plants and combined heat and power plants (CHPs) has increased, caused by an increase in both the number and size of CHPs. This places large demands on the logistics system supplying these plants with fuel, with a particular interest in the use of alternative modes of transport such as rail and sea. The aim of this paper is to identify the industry actors’ requirements, constraints, and preferences regarding the wood-biofuel supply chain and to identify the logistical challenges this entails, as well as how this impacts the opportunity for an increased use of alternative transport solutions. A survey was sent to all Swedish CHPs, combined with six interviews with transport companies, terminal operators, and forest companies. The study shows that the industry has a local focus that limits potential logistics and sourcing solutions. It is also challenged by urban sprawl, with expanding residential areas close to the CHPs putting further constraints on the operations. Significant variations in fuel demand, depending on unpredictable outside temperature and seasonal variation, is a further challenge. The low density of the fuel has a negative impact on transport costs and introduces a trade-off between chipping close to the forest to increase density versus more efficient chipping at the CHP. Intermodal transport only used by large plants, driven by a shortage of local fuel. © 2020 The Authors

  • 8.
    Bach, Andreas
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Forsström, Ellinor
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Haraldson, Sandra
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Holmgren, Kristina
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Lind, Kenneth
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Lind, Mikael
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Piehl, Hampus
    RISE Research Institutes of Sweden, Säkerhet och transport, Elektrifiering och pålitlighet.
    Raza, Zeeshan
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Rydbergh, Torbjörn
    Marine Benchmark, Sweden.
    HAMNEN SOM ENERGINOD : Ett koncept för hamnens roll i omställningen mot ett hållbart transportsystem2022Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Transportsystemet står inför en enorm utmaning då trycket på genomförandet av hållbara operationer aldrig varit större. Enligt IEA står transportsektorn för 16% av det totala koldioxidutsläppet i världen som med nödvändighet måste minska för att vi ska kunna lämna efter oss en planet med resurser för framtida generationer. Utmaningen kräver att alla delar av transportsystemet gör sitt bidrag, oavsett om det handlar om transportoperatörer, transportnoder, myndigheter på såväl lokal, regional som global nivå och tvärs samtliga transportslag. Det slutar dock inte där, det är lika viktigt att de som konstruerar olika typer av lastbärare och fordon för både gods- och persontransporter också beaktar den energi som förväntas vara tillgänglig i rätt kvantitet och till rätt pris. Energiproducenter behöver också tillgodose att efterfrågade energibärare produceras och finns att tillgå vid rätt plats och i tillräcklig kvantitet då den behövs. Detta är i linje med de behov av insatser som Sveriges regering lyfter inom transporteffektivitet, hållbara förnybara drivmedel samt energieffektiva fordon och fartyg, för att reducera Sveriges territoriella CO2 utsläpp i linje med de globala målen. En viktig del av transportsystemet är hamnar som har fönster mot flera olika transportslag och utgör multimodala noder som förväntas ombesörja en så sömlös övergång mellan olika transportslag som möjligt, såsom till/från sjö, järnväg och väg. Svenska hamnar är inget undantag, utan i Sverige med sin längsta europeiska kustremsa behöver Sveriges hamnar också etablera tillräcklig kapabilitet för att hantera såväl inhemska transportbehov som förväntade transporter för import och export på ett hållbart sätt. Hamnar står inför utmaningen att både bedriva sina operationer på ett så hållbart sätt som möjligt genom nyttjande av fossilfri energi, att förse besökare med fossilfria energibärare, och att balansera sitt nyttjande och distribution av hållbar energi med de behov som omgivningen har. Organisationer med lastbilar, tåg, och fartyg som besöker en transportnod, däribland hamnar, förväntar sig att de kan försörjas med viss energi. Transportnoder kan således inte bara betraktas utifrån att vara en effektiv omlastningspunkt, utan behöver också betraktas utifrån den roll som transportnoden har och kan komma att ta i den del av energisystemet som relaterar till transportsystemet. Hamnar som transportnoder behöver således etablera en förmåga som energinod. I föreliggande projekt har trender beaktats för utvecklingen inom olika transportslag, intervjuer genomförts med svenska hamnar samt en enkätundersökning genomförts riktad till en majoritet av Sveriges hamnar. I projektet identifieras att de viktigaste drivkrafterna för hamnarnas hållbarhets- och omställningsarbete är kundkrav, kostnadsbesparingar, hamnens interna målsättning (ofta baserad på ägarnas krav och vision) samt regelverk. Slutsatsen är att Sveriges hamnar har en stark ambition att utveckla sin förmåga som energinod för olika roller. Samtidigt råder en villrådighet om vilka satsningar som skulle ge störst effekter för hamnens verksamhet. Viktigt att notera är också att olika hamnar har olika förutsättningar och roller i transportsystemet, beroende på dess geografiska placering, storlek och typ av gods / passagerare som hanteras. Samtidigt görs stora investeringar i Sveriges hamnsystem, för att proaktivt utveckla en kapabilitet att möta dagens och morgondagens transportbehov, särskilt i ljuset av den omflyttning som sker från vägbundna transporter till järnväg och sjö. Det är vanligt att hamnar etablerar inlandsterminalskapabilitet, d v s skapar förmåga för omlastning mellan tåg och väg där inte någon sjötransport behöver vara inblandad. Många av Sveriges järnvägsoperatörer ser hamnar som strategiska noder i järnvägssystemet. Dessutom det är tydligt från intervjuerna, vilket även styrks av enkätsvar, att respondenterna anser att otillräckliga finansiella medel, höga kostnader och skatt, omogen teknik, infrastruktur, effekt, standardisering, kompetens, och politisk otydlighet är de största utmaningar som påverkar svenska hamnars roll i hållbarhets- och omställningsarbete. Baserat på genomförd trend- och nulägesanalys föreslås en mognadsmodell som rådgivande för hamnens proaktiva utveckling av sin energinodskapacitet. Denna modell tar utgångspunkt i att hamnen etablerar en energistrategi som tar höjd för nödvändiga samarbeten och investeringar som de både blir tvingade till genom regelverk, påverkade av genom beslut och själva har rådighet över. Hamnarna är tydliga med att huvudverksamheten är att utgöra en transportnod, men att de, för att möjliggöra en omställning mot ett hållbart transportsystem, också behöver ge utrymme för andra aktörer, såsom energiproducenter och energidistributörer att bedriva sin verksamhet relaterat till hamnens geografiska område. Således behöver det kluster av aktörer som ingår i hamnen som nod expanderas till att också innefatta producenter och distributörer av energi. Hamnens energistrategi är rådgivande för att hamnen skall kunna etablera en förmåga som säkerställer att de krav som hamnens operationer, hamnens besökare och hamnens roll med sin geografiska placering, möts. Föreslagen mognadsmodell riktar uppmärksamhet just till dessa nivåer av förmåga och skapar grunder för formuleringen av en proaktiv strategi för den enskilda hamnens roll i transportsystemets energiomställning. En viktig grund blir då att simulera framtida energibehov, såsom inom elförsörjnings- och eldistributionsområdet, men även för andra energibärare, varför detta projekt föreslår ett fortsättningsprojekt där förväntade energibehov kan simuleras och bli rådgivande för strategi, samverkan och investering för Sveriges hamnar. En sådan simuleringsmodell bygger på hamnens digitala förmåga att fånga och använda data från operationer för att säkerställa att hamnen bidrar till transporteffektivitet, användning av hållbara förnybara drivmedel samt energieffektiva fordon och fartyg. Samspelet mellan hamnen som energinod och transportbärares kapabilitet att drivas på hållbar energi samt energiproducenters/energidistributörers förmåga att tillhandahålla fossilfri energi, utgör grunden till fossilfria transporter. Fossilfria väg-, järnvägs- och sjötransporter kan således inte etableras utan att ta hänsyn till alla ingående komponenter. I denna nödvändiga transformation har hamnar och andra transportnoder en nyckelroll.

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  • 9.
    Burden, Håkan
    et al.
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Stenberg, Susanne
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Carlgren, Lisa
    RISE Research Institutes of Sweden, Digitala system, Prototypande samhälle.
    Sjöblom, Ted
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Policylabb Smarta Fartyg2022Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Swedish Shipping Policy Lab

    Smart ships, or Maritime Autonomous Surface Ships as they are also known, have a great potential to advance shipping and sustainable development through optimisation of operations and maintenance. In situations that pose a risk to humans or where humans tend to lose their concentration, smart ships can also contribute to increased safety onboard and for the environment. In short, smart ships are suitable for operations that are dirty, dull and dangerous. The Swedish Shipping Policy Lab was an initiative to support on-going projects within smart shipping with policy-developing activities with the ambition to strengthen Swedish competitiveness. The project has actively strived for a systematic approach to how shipowners, technology developers and authorities among others can foster policy development and innovation in relation to smart ships. As an outcome the project has identified three policies related to the investigated cases (see Appendix G for more details): 1. Navigational assistance from land – A shared statement by the Swedish Maritime Administration and the Swedish Transport Agency on the role of navigational assistance from land and the need to further investigate the service before it can be regulated in more detail. 2. The Ljusterö Ferry – Certification of ferries is commonly done in relation to an established and consistent set of technical requirements. For smart ships such as the new road ferries procured for the Ljusterö-connection it is reasonable to complement traditional certification with a safety case to ensure that the ship is seaworthy. 3. Smart maritime drones – Ships less than five meters long that do not carry passengers are excluded from national rules regulating the supervision performed by the Swedish Transport Agency. As long as there is no explicit need to inspect a specific ship, the probability of a supervision is low. If an inspection were to incur, it is necessary to show how the smart ship and its operation complies to applicable regulation in terms of laws and collision avoidance. Despite the maritime sector having a long tradition of international governance there are still no international instruments explicitly for smart ships. A conclusion from the policy lab is that while such work is ongoing, there is room for the flag states and their authorities to develop and operate smart ships in accordance with national policies. Or, to paraphrase, smart ships seem suitable for operations that are dirty, dull, dangerous and domestic.

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  • 10.
    Burden, Håkan
    et al.
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Stenberg, Susanne
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Carlgren, Lisa
    RISE Research Institutes of Sweden, Digitala system, Prototypande samhälle.
    Sjöblom, Ted
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    The Swedish policy lab for maritime autonomous surface ships2022Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Swedish policy lab for maritime autonomous surface ships, or smart ships, explored three use cases for developing policy in practice. The policies regard smart ships on national waters: one short-term written policy identifying the next shared step for two authorities to position remote navigational assistance as a new service, giving the maritime ecosystem one official position to relate to; one informal policy relying on a mutual trust, where information sharing between an operator of small, unmanned ships and the supervisory authority enables critical competence building; and one evolving policy on the process of certifying autonomous or remote operated functions using non-standardized technology. In conclusion, despite shipping being explicitly regulated internationally we found that there is substantial leeway for national policies regarding smart ships on national waters.

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  • 11.
    Burden, Håkan
    et al.
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Stenberg, Susanne
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Carlgren, Lisa
    RISE Research Institutes of Sweden, Digitala system, Prototypande samhälle.
    Sjöblom, Ted
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    The Swedish policy lab for maritime autonomous surface ships2023Ingår i: Transportation Research Procedia, ISSN 2352-1457, Vol. 72, s. 1840-1847Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Swedish policy lab for maritime autonomous surface ships, or smart ships, explored three use cases for developing policy in practice. The policies regard smart ships on national waters: one short-term written policy identifying the next shared step for two authorities to position remote navigational assistance as a new service, giving the maritime ecosystem one official position to relate to; one informal policy relying on a mutual trust, where information sharing between an operator of small, unmanned ships and the supervisory authority enables critical competence building; and one evolving policy on the process of certifying autonomous or remote operated functions using non-standardized technology. In conclusion, despite shipping being explicitly regulated internationally we found that there is substantial leeway for national policies regarding smart ships on national waters.

  • 12.
    Carlsson, Annika
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Elektrifiering och pålitlighet.
    Fast, Lars
    RISE Research Institutes of Sweden, Säkerhet och transport, Elektrifiering och pålitlighet.
    Nordin Fürdös, Axel
    RISE Research Institutes of Sweden, Säkerhet och transport, Elektrifiering och pålitlighet.
    Adams, Paul
    RISE Research Institutes of Sweden, Säkerhet och transport, Elektrifiering och pålitlighet.
    Forsström, Ellinor
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Haberl, Felix
    Volvo, Sweden.
    Johansson, Monica
    Volvo, Sweden.
    Parthav, Desai
    Volvo, Sweden.
    Flytande väte som ett logistiskt bränsle – En förstudie2022Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Energibolagen gör stora investeringar för att tillhandahålla infrastruktur för produktion, distribution och tankning av vätgas. Det är därför viktigt att hitta de mest effektiva och genomförbara scenarierna för väte i samhället. Detta innebär att välja mellan värdekedjor för flytande väte (LH2) eller komprimerad vätgas (CGH2) i stegen från produktion till lagring ombord på fordon inom transportsegment, till exempel tunga lastbilar. Under projektet övervägdes också det ännu oetablerade konceptet med kryo-komprimerad vätgas (CcH2). Projektet syftade till att identifiera de kritiska utmaningarna och nuvarande begränsningar som påverkar den utbredda användningen av väte som bränsle för transporttillämpningar. Det har fokuserat på att öka kunskapen om teknologier som kan göra LH2- eller CGH2-infrastruktur och fordonsanvändning effektivare och säkrare, genom att bedöma den aktuella teknikens nivå såväl som mognad samt potential för ny teknik. I detta ingick också ett segment fokuserat på säkerhetsrisker kring alternativen längs de senare delarna av värdekedjan. Projektet som helhet genomfördes som en litteraturstudie. För teknologimognaden i olika delar av värdekedjan har projektet sammanfattat resultaten i ett kategoriseringssystem på mycket hög nivå, se tabell nedan. Definitionerna är huvudsakligen kvalitativa i följande kategorier: • Etablerad (används i större skala, ~TRL 9-10) • Beprövat koncept (demonstranter eller snart det här stadiet, ~TRL 7-8) • Initial design (inga offentliga demonstratorer tillgängliga, ~TRL 3-6) • Osäker tillämplighet (tillämpligheten fastställdes inte i detta arbete) • Ej tillämpbart (Kan inte användas för detta tillstånd av väte) Tabellen ovan ger också en översikt över de segment som ingår i rapporten. I kombination med den tekniska utvärderingen gjordes också en kvalitativ kostnadsanalys av de olika fastillstånden för väte. Här indikeras att även om LH2 har en högre kostnad i den inledande delen av värdekedjan, har den lägre kostnader i slutsegmenten. Därför är det möjligt att slutpriset för användaren blir liknande för både LH2 och CGH2. Hela kostnaden kan jämföras först när LH2 tankstationer och fordon byggs offentligt och kostnadsinformation är tillgänglig. Detsamma gäller för CcH2. Under förstudien för säkerhet, föreskrifter och standarder kom följande slutsats: Ur ett säkerhetsperspektiv finns det inga oöverstigliga barriärer med avseende på användningen av LH2 ombord på tunga vägfordon på medellång sikt, men det finns flera utmaningar att övervinna, inte minst på kort sikt. Inom EU finns regler som tillåter typgodkännande av tunga vägfordon med LH2 lagringssystem. Dessa är dock baserade på arbete som utfördes för 15 - 20 år sedan och är allmänt erkända som i behov av att uppdateras och valideras på samma sätt som CGH2 vägfordonsreglerna har varit. Det finns även en brist på uppdaterade industristandarder för LH2-lagringssystem för vägfordon. En särskild lucka är avsaknaden av en uppdaterad standard som kan refereras till i föreskrifter för munstycket i tanköppningens geometri. För LH2-påfyllningsstationer som helhet finns det dessutom inga lämpliga, uppdaterade internationella standarder, så det finns en risk att enskilda länder ställer sina egna krav. Sammantaget drog projektet slutsatsen att det inte finns några oöverkomliga hinder för implementeringen av LH2. Det är en genomförbar värdekedja ur både teknologiska-, kostnads- och säkerhetsperspektiv. Den kan också i framtiden bli jämförbar med den mer beprövade värdekedjan CGH2, men vissa initiala hinder och investeringar måste övervinnas.

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  • 13.
    Castrellon, Juan Pablo
    et al.
    Chalmers University of Technology, Sweden; Universidad Nacional de Colombia, Colombia.
    Sanchez-Diaz, Ivan
    Chalmers University of Technology, Sweden.
    Roso, Violeta
    Chalmers University of Technology, Sweden.
    Altuntas-Vural, Ceren
    Chalmers University of Technology, Sweden.
    Rogerson, Sara
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Santén, Vendela
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Kalahasthi, L. K.
    Chalmers University of Technology, Sweden.
    Assessing the eco-efficiency benefits of empty container repositioning strategies via dry ports2023Ingår i: Transportation Research Part D: Transport and Environment, ISSN 1361-9209, E-ISSN 1879-2340, Vol. 120, artikel-id 103778Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Trade imbalances and global disturbances generate mismatches in the supply and demand of empty containers (ECs) that elevate the need for empty container repositioning (ECR). This research investigated dry ports as a potential means to minimize EC movements, and thus reduce costs and emissions. We assessed the environmental and economic effects of two ECR strategies via dry ports—street turns and extended free temporary storage—considering different scenarios of collaboration between shipping lines with different levels of container substitution. A multi-paradigm simulation combined agent-based and discrete-event modelling to represent flows and estimate kilometers travelled, CO2 emissions, and costs resulting from combinations of ECR strategies and scenarios. Full ownership container substitution combined with extended free temporary storage at the dry port (FTDP) most improved ECR metrics, despite implementation challenges. Our results may be instrumental in increasing shipping lines’ collaboration while reducing environmental impacts in up to 32 % of the inland ECR emissions. © 2023 The Author(s)

  • 14.
    Coslovich, Franciesco
    et al.
    Chalmers University of Technology, Sweden.
    Kjellberg, Martin
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Östberg, Magnus
    Flowtech International AB, Sweden.
    Janson, Carl-Erik
    Chalmers University of Technology, Sweden.
    Added resistance, heave and pitch for the KVLCC2 tanker using a fully nonlinear unsteady potential flow boundary element method2021Ingår i: Ocean Engineering, ISSN 0029-8018, E-ISSN 1873-5258, Vol. 229, artikel-id 108935Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, a fully nonlinear unsteady potential flow method is used to predict added resistance, heave and pitch for the KVLCC2 hull in regular head waves at design speed. The method presents a nonlinear decomposition of the velocity potential and the wave field and an adaptive grid refinement. A formulation for the acceleration potential is used to obtain the pressure. To improve computational efficiency, a Barnes-Hut algorithm is introduced. A grid dependency study and a study on the impact of different time steps on the solution are performed. Numerical results have been compared with experimental data for the design speed. A general good agreement is found for added resistance, especially for longer waves. Heave and pitch are properly computed for all wave lengths in the range λ/Lpp=0.4 to 1.4. © 2021 The Author(s)

  • 15.
    Costa, Nicole
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Final and Complete Report of SSPA’s Tasks in FAMOS Odin2018Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This document reports the methods used and results obtained for the tasks established between SSPA and the FAMOS Odin project, as follows:Baseline analysis of traffic in the Baltic Sea, using collected AlS dataa.Analysis of safe Under-Keel Clearance (UKC) used in today’s trafficb.Analysis to which extent transport capacity is currently limited by UKCc.Calculation of the added fuel consumption caused by the squat effectSimulation of traffic based on improved bathymetry and UKC controla.Present energy efficient routing options with regards to distance, UKC and squatb.Calculate the benefits of optimized UKC for increased cargo capacityc.Use and test S-102 data as a basis for these analyses.This document reports as well the active partner’s budget outcomes, milestones and gains accomplished within the project timeframe.Analyses based on bathymetric and Automatic Identification System (AIS) data evidenced, for a chosen area of interest in the Baltic Sea, that tankers may be limited by UKC and as a result carry less cargo, which could amount to 1% more of the total cargo transported through the Baltic Sea, according to the model used. The results also show the linear relationship between the increase of speed and squat effect with the subsequent increase of water resistance and need of energy to propel the ship, signifying a direct increase in fuel consumption. Finally, the results emphasize certain regions of the Baltic Sea where routes could especially benefit from optimization for reduced fuel consumption, yet optimization results may depend on different route parameters prioritized by the mariner (e.g, speed vs. Estimated Time of Arrival (ETA)).Some recommendations for futures stages of this project include access to higher-fidelity depth data for Swedish waters to refine the studies described in this report, as well as the inclusion of a qualitative research component to investigate how UKC is perceived by the mariners or what reasons they may have for keeping a certain UKC or loading cargo to a certain weight.

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  • 16.
    Costa, Nicole
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Weber, Reto
    Chalmers University of Technology, Sweden.
    Olsson, Fredrik
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Algell, Johan
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Testing Proof of Concept of a Web-Based Ship Manoeuvring Training Tool in the Classroom2019Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Currently, real-time ship manoeuvring simulations are confined to static environments e.g., desktop/full-mission bridge simulators. Seaman Online™ is a novel web-based ship manoeuvring training tool allowing students and professional mariners to practice manoeuvres in ports and confined waters from their personal computers. This paper describes the tool’s first-time implementation in a Master Mariner university programme. The students were asked to complete a post-questionnaire regarding their use experience and the results were discussed between the course instructors and the toolproviding organization at two debriefings. The aim was to obtain feedback about (a) the usefulness of the tool in manoeuvring training; (b) further design improvements and usability; and (c) how to best incorporate it into the programme curriculum in coming academic years for improved user experience. Results revealed usability and maturity issues and the need for further guidance on simulation-based training objectives and limitations. Overall, the tool’s usefulness and potential in individual manoeuvring training were demonstrated.

  • 17.
    Costa, Nicole
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Williamsson, Jon
    Ekholm, Johan
    Santén, Vendela
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Rogerson, Sara
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Borgh, Martin
    Connecting vessels to shoreside electricity in Sweden2022Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The purpose of the KAJ-EL project was to offer decision support to ports and shipping companies about the implementation and use of shoreside electricity in Swedish ports. More specifically, this project investigated the following, among other questions related to shore power: • the driving forces and barriers among ports and shipping companies to offer or use shore power; • the decision making, steps and actors involved in the process of adopting shore power; • the costs and business arrangements for installing and operating shore power; • the challenges in the installation and operation of shore power; • the different shore power equipment used in Swedish ports and on board vessels; • the actions and condition to realise OPS adoption to a larger extent. The project group included researchers and experts in shipping, transport, logistics, economics, and human factors from SSPA and the University of Gothenburg, and included industry partners Svensk Sjöfart (Swedish Ship Owners’ Association) and Sveriges Hamnar (Ports of Sweden). In addition, industry and authorities were involved in a reference group with representatives from shipping companies, ports and electricity providers. Interviews were performed with various ports in Sweden, a port in Norway (Kristiansand) as well as the US ports of Long Beach and Seattle to compare the perspectives. Shipping companies were interviewed, as were a number of OPS equipment manufacturers, national grid operators and electricity providers. Two workshops and a final seminar were also conducted. This report presents an overview of the OPS situation in Sweden and provides principles for business models as well as recommendations for ports’ and shipping companies’ OPS work. It can be noted that Sweden is at the European forefront of OPS in the sense that it currently has nine cities offering OPS, with main focus so far on the ro-pax and ferry segment. Actors, in particular ports, perceive that the regulatory pressure to offer OPS is increasing and the knowledge about OPS, especially among non-experienced ports, is still limited. Further guidance on OPS installations and operations is therefore needed, in terms of the financial, business, technical and operational issues that the actors must deal with. One major question is how to secure the electricity supply to the ports. Collaboration between actors is key to successful OPS implementation and a higher level of standardisation can facilitate technical choices. Several areas in need of further research are highlighted in this report, such as investigating possible future power demand scenarios from using OPS, and supply strategies for ports. The project received funding from Trafikverket (The Swedish Transport Administration).

  • 18.
    Dahlbom, Sixten
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Sanfridson, Martin
    RISE Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Sjöblom, Ted
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Evaluation of Detection Principles and Challenges in Early Detection of Thermal Runaway in Batteries2023Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The amount of battery electrical vehicles (BEVs) carried as cargo on ro-ro ships is increasing. The possibility of thermal runaway in a lithium-ion battery makes BEVs a different fire risk compared to internal combustion engine vehicles (ICEV). One of the challenges that arise is how to detect a thermal runaway early. Current detection systems in ro-ro spaces generally consist of smoke and/or heat detection. To identify potential techniques and challenges for detection of a thermal runaway, as early as possible, tests with batteries and detectors are needed. Tests with one battery cell were performed inside an ISO container (with almost negligible ventilation) as well as in an open room with moderate ventilation (14 air changes per hour). Point-type detectors (two smoke and heat detectors, one CO detector, and one LEL detector), thermal imaging, video analytics, and light detection and ranging (LIDAR) were evaluated in the tests. A total of 14 tests were conducted. The detectors were evaluated in different positions relative to the battery cell and comparative tests with wood-sticks were performed to investigate the detectors’ ability to detect a more conventional source of fire. Based on the results, it can be concluded that early detection of thermal runaway in batteries is possible in principle. However, detection is a matter of circumstances e.g., ventilation, gas/smoke production and the location of the detector(s). The result indicates that detection in a small and confined space is relatively manageable, but detection in a large and open space could be more of a challenge. If the gas/smoke is cooled down it may sink and spread along the floor/deck, instead of rising and spreading along the ceiling. This would be a challenge with current smoke detectors installed in the ceiling. Shielding may be a problem, especially with LIDAR and thermal imaging. Future research should address full-scale tests, and it is recommended to include Optical Gas Imaging (OGI) as a mean of detection.

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  • 19.
    Daniel, Vergara
    et al.
    Chalmers University of Technology, Sweden.
    Alexandersson, Martin
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Chalmers University of Technology, Sweden.
    Xiao, Lang
    Chalmers University of Technology, Sweden.
    Wengang, Mao
    Chalmers University of Technology, Sweden.
    A machine learning based Bayesian decision support system for efficient navigation of double-ended ferries2023Ingår i: Journal of Ocean Engineering and Science, ISSN 2468-0133Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ships can be operated more efficiently by utilizing intelligent decision support integrated with onboard data collection systems. In this study, a Bayesian optimization-based decision support system, which utilizes ship performance models built by machine learning methods, is proposed to help determine the operational set-points of two engines for double-ended ferries. By optimizing the ferries’ power allocation between the stern and bow engines, the Decision Support System (DSS) will simultaneously attempt to keep the ETA of the ferry fixed under a set of operational constraints using the Bayesian optimization. Its objective is to minimize fuel consumption along individual trips. Based on simulation environment, the DSS can reduce at maximum 40 % fuel consumption with no significant change of the ETA. Final full-scale experiments of a double-ended ferry demonstrated an average of 15 %, where at least half of this saving was achieved by the optimized power allocation between bow and stern engines. 

  • 20.
    de Alwis, Pahansen
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Riding the waves: Kidney belt-mounted accelerometers to measure lumbar spine vibrations in high-speed craft occupants2023Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The scientific investigation into the viability of employing kidney-belt-mounted accelerometers to quantify shock and vibration exposure in the lumbar spine region of occupants in high-speed marine craft, and their concordance with prevailing standards, has been heretofore unexplored. Addressing this research gap, a series of meticulously designed laboratory and field experiments were undertaken. In the laboratory setting, two test subjects were engaged in predefined body movements, with accelerations recorded using both body-mounted and kidney-beltmounted accelerometers. This controlled environment allowed for a comparative analysis of the efficacy of the two accelerometer configurations in capturing lumbar spine accelerations. Field experiments expanded upon these findings, involving the recording of acceleration exposures during a high-speed marine craft exercise. The kidney-beltmounted accelerometers were utilized alongside seat-mounted accelerometers to assess their applicability in real-world dynamic conditions. The results revealed that kidney-belt-mounted accelerometers effectively captured lumbar spine accelerations during basic body movements, particularly when the torso was maintained in an upright position. However, the translation of these measurements into a framework aligned with existing international standards encountered substantial challenges during the field experiment. This study underscores the potential utility of kidney-belt-mounted accelerometers for lumbar spine acceleration measurement in controlled environments. Nevertheless, the complexities associated with aligning these measurements with established international standards were evident, highlighting the need for further consideration and refinement. The implications of this research extend to the recognition that current standards may not fully address the intricacies of shock and vibration exposure in the lumbar spine region within the dynamic context of high-speed marine craft environments. Consequently, there is a clear call for the development of standards specifically tailored to these operational conditions to ensure a comprehensive and accurate assessment of lumbar spine health in marine craft occupants.

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  • 21.
    de Alwis, Pahansen
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Garme, Karl
    KTH Royal Institute of Technology, Sweden.
    Feasibility of Using Kidney-Belt-Mounted Accelerometers for Measuring Shock and Vibration Exerted on the Lumbar Spine Region of High-Speed Marine Craft Occupants2023Ingår i: Progress in Marine Science and Technology, IOS Press BV , 2023, Vol. 7, s. 233-240Konferensbidrag (Refereegranskat)
    Abstract [en]

    The feasibility of using kidney-belt-mounted accelerometers for measuring the shock and vibration exposure in the lumbar spine region of high-speed marine craft occupants and evaluating them on a par with the current standards remain largely unexplored in scientific literature. To address this gap a series of laboratory and field experiments were conducted. In the laboratory experiments, two test subjects performed predefined body movements while accelerations were measured using body-mounted and kidney-belt-mounted accelerometers. Field experiments involved recording acceleration exposures of two test subjects using the kidney belt arrangement and seat-mounted accelerometers during a high-speed marine craft exercise. Results suggest that kidney-belt-mounted accelerometers effectively measure lumbar spine accelerations during basic body movements with an upright torso. However, evaluating vibration exposures measured with the kidney belt arrangement using existing international standards proved challenging in the field experiment. 

  • 22.
    Dixit, Saubhagya
    et al.
    Scientist Central Pollution Control Board, India.
    Rao, K Ramachandra
    Indian Institute of Technology, India.
    Tiwari, Geetam
    Indian Institute of Technology, India.
    von Wieding, Sönke
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Urban freight characteristics and externalities – A comparative study of Gothenburg (Sweden) and Delhi (India)2022Ingår i: Journal of Transport and Supply Chain Management, ISSN 2310-8789, E-ISSN 1995-5235, Vol. 16, artikel-id a629Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: The urban freight transportation (UFT) system is an essential facilitator for the smooth functioning of city logistics. It also contributes significantly to transportation-related issues, such as vehicular congestion, pollution, accidents, infrastructure damage and other related problems. Objectives: This study aimed to understand and compare the urban freight traffic characteristics and their impact in two cities: Gothenburg, Sweden and Delhi, India, having high socio-economic differences. The findings of this study will be helpful for practitioners and policymakers in the development and successful implementation of UFT management policies. Method: Using the cordon count (traffic data), retailers’ interviews (receivers’ data) and freight vehicle drivers’ interviews, UFT characteristics such as sector-specific contribution, trip characteristics, vehicular characteristics and negative impacts in terms of external cost to society are evaluated. This study also discusses the prediction of attracted trips in the study zone using freight trip attraction (models. Results: About 75% of the trips in Gothenburg and 92% of the trips in Delhi are made by light commercial and other small-sized vehicles. Gothenburg has formally organised sectors involved in freight vehicle movement; however, Delhi has informally organised sectors. Conclusion: The results revealed substantial differences in characteristics of freight trip operations in both the cities, compared with few similarities. Measures taken considering the specific local attributes of freight traffic and stakeholders’ requirement may lead to a sustainable transportation system in cities. © 2022. The Authors.

  • 23.
    Eriksson, Anna
    et al.
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Cederstav, Fredrik
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Ranäng, Sara
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Lyrberg, Magnus
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Einarson Lindvall, Elin
    RISE Research Institutes of Sweden, Samhällsbyggnad, Systemomställning och tjänsteinnovation.
    von Wieding, Sönke
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Slutrapport inom Gothenburg Green City Zone (GGCZ): Metodik för analys och införande av klimatneutrala mobilitets- och transportlösningar i städer2024Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Denna rapport är ett arbetsdokument som har efterfrågats i arbetet inom Gothenburg Green City Zone (GGCZ), där det pågår en process för att ta fram en mer detaljerad planering för en övergång till helt fossilfria transporter i Göteborg. Rapporten resonerar först kring zonbegreppet, vilken forskning som tidigare gjorts, vilka slags zoner som redan finns och som implementerats i Sverige och Europa. Rapporten föreslår sedan en metodik för hur zoner kan definieras och hur en generell zonindelning skulle kunna upprättas som skulle kunna användas som mall för både Göteborg och andra städer. Arbetet är inte färdigt utan kommer att fortsätta under kommande år både inom RISE och tillsammans med övriga samarbetspartners. Det som kvarstår är att definiera i detalj vilka parametrar och egenskaper som gör en viss zon unik, exempelvis genom mätetal som stadsdelars täthet, demografi, socioekonomiska förhållanden, infrastruktur samt befintlig framkomlighet. Målet med arbetet har varit att utveckla och förbättra kunskapen om zonmetodiken, visa på dess möjliga fördelar och utveckla ett verktyg för att användas i omställningen och att hjälpa Göteborg och andra städer att lyckas med omställningen mot klimatneutrala transporter till år 2030.

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    DIVA_RISE-Rapport_GGCZ
  • 24.
    Eriksson, Anna
    et al.
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    von Wieding, Sönke
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Gestrelius, Sara
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Lyrberg, Magnus
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Ranäng, Sara
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system.
    Carlén, Vanja
    Closer, Sweden.
    Hansson, Marcus
    Closer, Sweden.
    REDIG- Regionala godshubbar i Göteborg: FÖRSTUDIE – DRIVE SWEDEN2023Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Denna rapport är ett resultat av en förstudie kring en logistik- och transportlösning (som kan realiseras i form av en gemensam hubb) för aktörer som är placerade i evenemangsstråket i Göteborg. Rapporten svarar på frågor kring nulägesanalys av aktörernas logistiklösningar, leveranstrafik inom evenemangsstråket, samt hur leveranstrafik kan se ut under 2030+ om inga förändringar i leverans/logistikupplägget görs. En viktig slutsats som framgår är att det krävs åtgärder som minskar leveranstrafiken, eftersom elektrifiering av fordon inte kan eliminera trängsel och buller som står för den största delen av de samhällsekonomiska kostnaderna. Utan förändringar i logistikupplägget och fordonsflottan förväntas de samhällsekonomiska kostnaderna öka med cirka 30%. Förändringar i logistikupplägget kan nås genom ett optimerad trafikflöde, vilket i sin tur kan realiseras genom en gemensam samlastningshubb för små och fragmenterade flöden som kan minska antalet anlöp och fordonstrafiken i området. Baserat på intervjuer med aktörerna, studiebesök, studerande av underlag, workshops och analys av logistikbehoven, kan det sammanfattas att verksamheterna, utmaningar och logistikbehoven i stort sett är ganska lika. En gemensam extern hubb kan frigöra yta hos verksamheterna som kan användas för att skapa nya affärsmöjligheter. En möjlighet för att upphandla en tredjeparts logistik- och transportlösning är att bygga ett konsortium där alla aktörer delar på kostnaden för terminalhantering samt samlastning/samkörning. Det finns stora möjligheter att hitta lösningar för logistikhubb som uppfyller kraven på geografisk närhet och säkra leveranser i trafiksystemet – och det är klokt att anpassa leveranstider för att undvika trängsel. Det finns en vilja hos aktörerna att minska transporterna, anpassa sin verksamhet för effektivisering vid mottagning och förvaring, ställa om mot fossilfrihet och på det sättet bidra till transporteffektivitet som krävs för att nå mål inom klimatneutralitet 2030. Det finns stora behov för förändring i trafikflödet inom GGCZ och det finns en stor potential att optimera det genom att konsolidera och styra leveranser.

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  • 25.
    Eskilsson, Claes
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Aalborg University, Denmark.
    Pashami, Sepideh
    RISE Research Institutes of Sweden, Digitala system, Datavetenskap.
    Holst, Anders
    RISE Research Institutes of Sweden, Digitala system, Datavetenskap.
    Palm, Johannes
    Sigma Energy & Marine, Sweden.
    Estimation of nonlinear forces acting on floating bodies using machine learning2023Ingår i: Advances in the Analysis and Design of Marine Structures / [ed] J. W. Ringsberg, C. Guedes Soares, CRC Press, 2023, s. 63-72Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    Numerical models used in the design of floating bodies routinely rely on linear hydrodynamics. Extensions for hydrodynamic nonlinearities can be approximated using e.g. Morison type drag and nonlinear Froude-Krylov forces. This paper aims to improve the approximation of nonlinear forces acting on floating bodies by using machine learning (ML). Many ML models are general function approximators and therefore suitable for representing such nonlinear correction terms. A hierarchical modelling approach is used to build mappings between higher-fidelity simulations and the linear method. The ML corrections are built up for FNPF, Euler and RANS simulations. Results for decay tests of a sphere in model scale using recurrent neural networks (RNN) are presented. The RNN algorithm is shown to satisfactory predict the correction terms if the most nonlinear case is used as training data. No difference in the performance of the RNN model is seen for the different hydrodynamic models.

  • 26.
    Eskilsson, Claes
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Pashami, Sepideh
    RISE Research Institutes of Sweden, Digitala system, Datavetenskap.
    Holst, Anders
    RISE Research Institutes of Sweden, Digitala system, Datavetenskap.
    Palm, Johannes
    Sigma Energy & Marine, Sweden.
    Hierarchical Approaches to Train Recurrent Neural Networks for Wave-Body Interaction Problems2023Ingår i: The Proceedings of the 33rd International Ocean and Polar Engineering Conference, 2023, Vol. 33, artikel-id 307Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a hybrid linear potential flow - machine learning (LPF-ML) model for simulating weakly nonlinear wave-body interaction problems. In this paper we focus on using hierarchical modelling for generating training data to be used with recurrent neural networks (RNNs) in order to derive nonlinear correction forces. Three different approaches are investigated: (i) a baseline method where data from a Reynolds averaged Navier Stokes (RANS) model is directly linked to data from a LPF model to generate nonlinear corrections; (ii) an approach in which we start from high-fidelity RANS simulations and build the nonlinear corrections by stepping down in the fidelity hierarchy; and (iii) a method starting from low-fidelity, successively moving up the fidelity staircase. The three approaches are evaluated for the simple test case of a heaving sphere. The results show that the baseline model performs best, as expected for this simple test case. Stepping up in the fidelity hierarchy very easily introduce errors that propagate through the hierarchical modelling via the correction forces. The baseline method was found to accurately predict the motion of the heaving sphere. The hierarchical approaches struggled with the task, with the approach that steps down in fidelity performing somewhat better of the two.

  • 27.
    Eskilsson, Claes
    et al.
    Aalborg University, Denmark.
    Shiri, Alex
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Katsidoniotaki, Eirini
    Uppsala University, Sweden.
    Solution verification of WECs: comparison of methods to estimate numerical uncertainties in the OES wave energy modelling task2023Ingår i: Proceedings of the 15th European Wave and Tidal Energy Conference, 2023, artikel-id 426Konferensbidrag (Refereegranskat)
    Abstract [en]

    High-fidelity models become more and more used in the wave energy sector. They offer a fully nonlinear simulation tool that in theory should encompass all linear and nonlinear forces acting on a wave energy converter (WEC). The focus on the studies using are usually dealing with validation. However, a validated model does not necessarily give reliable solutions. Solution verification is the methodology to estimate the numerical uncertainties related to a simulation. In this work we test four different approaches: the classical grid convergence index (GCI); a least-square version (LS-GCI), a simplified version of the least-square method (SLS-GCI) and the ITTC rec- ommended practice. The LS-GCI requires four or more solutions whereas the other three methods only need three solutions. We apply these methods to four different high- fidelity models for the case of a heaving sphere. We tested two parameters in the time-domain and two parameters in the frequency domain. It was found that the GCI and ITTC were hard to use on the frequency domain parameters as they require monotonic convergence which sometimes does not happen due to the differences in the solutions being very small. The SLS-GCI performed almost as well as the SL-GCI method and will be further investigated.

  • 28.
    Eskilsson, Claes
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Aalborg University, Denmark.
    Verao Fernandez, Gael
    Aalborg University, Denmark.
    Andersen, Jacob
    Aalborg University, Denmark.
    Palm, Johannes
    Sigma Energy & Marine, Sweden.
    Hydrodynamic simulations of a FOWT platform (1st FOWT comparative study) using Openfoam coupled to MoodyCore2023Ingår i: Proceedings of the 33rd International Ocean and Polar Engineering Conference, 2023, Vol. 33, artikel-id 068Konferensbidrag (Refereegranskat)
    Abstract [en]

    We numerically simulate the hydrodynamic response of a floating offshore wind turbine (FOWT) using CFD. The FOWT under consideration is a slack-moored 1:70 scale model of the UMaine VolturnUS-S semi-submersible platform. This set-up has been experimentally tested in the COAST Laboratory Ocean Basin at the University of Plymouth, UK. The test cases under consideration are (i) static equilibrium load cases, (ii) free decay tests and (iii) two focused wave cases with different wave steepness. The FOWT is modelled using a two-phase Navier-Stokes solver inside the OpenFOAM-v2006 framework. The catenary mooring is computed by dynamically solving the equations of motion for an elastic cable using the MoodyCore solver. The results of the static and decay tests are compared to the experimental values with only minor differences in motions and mooring forces. The focused wave cases are also shown to be in good agreement with measurements. The use of a one-way fluid-mooring coupling results in slightly higher mooring forces, but does not influence the motion response of the FOWT significantly.

  • 29.
    Eslamdoost, Arash
    et al.
    Chalmers University of Technology, Sweden.
    Larsson, Lars
    Chalmers University of Technology, Sweden.
    Brown, Matz
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    A device for reducing the resistance of transom stern hulls2021Ingår i: Ocean Engineering, ISSN 0029-8018, E-ISSN 1873-5258, Vol. 235, artikel-id 109351Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel idea to reduce the resistance of a transom stern hull in displacement and semi-planing modes is investigated. By placing a spoon-shaped device in the recirculating zone behind the transom, the momentum of the forward-moving water will be absorbed, and a pushing force generated on the device. Numerical and experimental techniques are applied on a transom stern hull to optimize the shape and position of the device and to explore in detail the physics behind the gain. For the towed hull at a Froude number of 0.4, the maximum measured resistance reduction is 11%, while the computed maximum reduction is 17%. In self-propulsion with one propeller, the measured power reduction is 15%. The power cannot be computed with the applied propeller model, which is an axial body-force distribution in the propeller disk, but the reduction in thrust using the device is 11%. More significant gains are possible at smaller Froude numbers, while the effect is reduced at higher Froude numbers. Larger gains are achieved by splitting the thrust on two propellers. © 2021 The Authors

  • 30.
    Finnsgård, Christian
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Liefvendahl, Mattias
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Ship power prediction with CFD in full scale2023Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This report demonstrates the qualifications of RISE to carry out CFD for ship self-propulsion, thus predicting the delivered power. The procedures were fully developed at SSPA which became fully integrated into the Maritime Department of RISE by 2023-01-01. An outline is given of the best-practice guidelines used at SSPA/RISE and how they comply with the relevant ITTC recommendations for verification and analysis. In addition, an overview is given of previous validation studies performed for a wide range of ships, including comparison with both model-scale and full-scale data. Complete references are provided to reports and publications in which these SSPA studies and methods are described in detail.

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  • 31.
    Finnsgård, Christian
    et al.
    SSPA Sweden AB, Sweden.
    Svanberg, Martin
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Blinge, Magnus
    Kan ett köpcenter försörjas med Närsjöfart?: En fallstudie med kartläggning av godsflöden till Torp köpcenter2016Konferensbidrag (Övrigt vetenskapligt)
  • 32.
    Forsman, F.
    et al.
    Chalmers University of Technology, Sweden.
    Finnsgård, Christian
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Chalmers University of Technology, Sweden.
    Teamwork as joint activity in sailing2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Sailing is a sport and activity that takes a long time both to learn and to master, as much of its competence-based knowledge is acquired through experience. Experiencebased learning is very important, time-intensive, and the factors for success are often tacit and hidden. Should these success factors become explicit and salient, learning would occur faster and produce obvious competitive advantages. This research was conducted by embedding on-going research results into two competitive sailing teams racing in different classes, one offshore keelboat racing with a crew of eight, and a one-design Star-class racing yacht with a crew of two. The data collection consisted of observations, interviews, and video recordings. The results were also verified with the crews to catch biases in the analysis process. A jibe, a specific but common maneuver was analyzed from the perspective of Common Ground within Joint Activity. Maneuvering a competitive offshore sail racer or a previously Olympic Star-class yacht are tasks that fulfill the requirements for Joint Activity. A high level of Common Ground is required for the effective coordination needed in order to perform at a high level and maintain the safety of the crew and equipment. Breakdowns in the coordination of maneuvers were observed, although they must be recorded on video for higher analysis reliability. To achieve greater validity, more and different maneuvers should be considered within the analysis. By better understanding the factors for success, sail racing teams can more quickly gain competence and thus competitive advantages. The research analyzes the teamwork found in sailing from the perspective of Joint Activity and Common Ground and provides insight into how to achieve performance improvements more efficiently. 

  • 33.
    Gerhardt, Frederik
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Case study: IMO minimum propulsion power to maintain the manoeuvrability of KVLCC2 tanker in adverse conditions2024Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The introduction of the EEDI more than a decade ago, slow steaming, and the wish to reduce bunkering costs have resulted in a trend to install less powerful engines in ships. To avoid vessels becoming underpowered and thus unsafe, the International Maritime Organization (IMO) has published a guideline regarding the “Minimum Propulsion Power to Maintain the Manoeuvrability of Ships in Adverse Conditions”. This report presents a case study that follows the IMO-guideline step by step and works out the minimum engine size for the KVLCC2 tanker. Using a combination of Computational Fluid Dynamics and model tests, the parameters and assumptions behind the guideline are discussed in some detail. Results show that it is particularly important to determine the added resistance in waves correctly because it dominates the power prediction. It becomes clear, that the selection of the propulsive factors, particularly the “thrust deduction factor” has a significant influence on results. The work summarised here is part of a wider project that aims to provide experimental benchmarking data for added resistance predictions. It has been sponsored by the Swedish Transport Administration (Trafikverket) under grant number TRV 2021/53938.

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  • 34.
    Gerhardt, Frederik
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Werner, Sofia
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Hörteborn, Axel
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Lundbäck, Olov
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Nisbet, J
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Olsson, Tobias
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    HORSES FOR COURSES: HOW TO SELECT THE “RIGHT” WIND PROPULSION SYSTEM AND HOW TO MAKE THE BUSINESS CASE2021Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Wind propulsion systems (WPS) are major investments and the decision to install them requires careful consideration of many complex questions. In this paper we present a systematic, scientific methodology to assess the benefits and drawbacks of such systems at the early concept stage of a vessel. The purpose is to provide guidance for shipowners and operators and help them make informed decisions. The proposed method was developed into a Software tool called ‘SEAMAN Winds’ and has been correlated to full scale results. The program draws on our large database of model tests, and CFD of hulls and wind propulsion technologies. It uses the intended trading routes of the vessel as an important input, typical output data are: a) performance values (ship speed, power requirements etc.) b) environmental parameters (CO2 avoided, EEDI and EEXI reduction, carbon intensity indicator) c) financial metrics (bunker savings, payback time for installation of WPS) Potential applications of the method include making the business case for one particular WPS or investigating in how far certain systems are more suited for a specific route than others.

  • 35.
    Gerhardt, Frederik
    et al.
    SSPA Sweden AB, Sweden.
    Werner, Sofia
    SSPA Sweden AB, Sweden.
    Li, Da-Qing
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. SSPA Sweden AB, Sweden.
    Malmek, Karolina
    SSPA Sweden AB, Sweden.
    Levelling the Playing Field: A Numerical Platform for the Fair Comparison of Wind Propulsion Systems2022Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Wind propulsion systems (WPS) are major investments and the decision to install them requires careful consideration of many complex questions. One of the recurring and challenging issues for ship owners is the choice of a suitable WPS for a specific ship and a specific operational pattern. Today most WPS providers offer on-demand case studies, but obviously the underlying performance prediction methodologies differ from provider to provider. This makes comparing different technologies from competing suppliers next to impossible. In this paper we present a numerical platform to compare different WPS of different makes, sizes, and costs in a fair way. The fundamental idea is to use aerodynamic WPS datasets that are independently verified by SSPA through wind tunnel test, sea trials or extensive CFD. This is combined with a hydrodynamic dataset from SSPAs database of tank tests. The same performance prediction method, identical routes and weather statistics are then used to determine Key Performance Indicators and financial metrics of the competing wind propulsion technologies. The purpose is to provide guidance for shipowners at the early concept stage of a vessel and help them select a system that suits their particular requirements.

  • 36.
    Grahn, Desirée
    et al.
    IVL Swedish Environmental Research Institute, Sweden.
    Hjort, Anders
    IVL Swedish Environmental Research Institute, Sweden.
    Jivén, Karl
    IVL Swedish Environmental Research Institute, Sweden.
    Forsström, Ellinor
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Gehandler, Jonatan
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Dahlbom, Sixten
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Förnybar flytande biogas (LBG) till sjöfart i praktiken2024Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Reducing the environmental and climate impact of shipping propelled by liquefied natural gas (LNG) requires the introduction of alternative fuels such as liquid biogas/biomethane (LBG) (Jivén et al., 2022). Today, only a small part of the biomethane produced in Sweden is liquefied into LBG and an even smaller part is used as fuel for shipping. The price and availability of biogas is governed by supply and demand in an international market where shipping, industry and heavy trucks demand biogas. The biogas then needs to be processed into upgraded biogas (biomethane) or LBG quality in order to be transported and used in the respective sectors inside and outside of Sweden. The trend is for a larger proportion of biogas to be liquefied into LBG. The market has thus gone from a local market, where biogas was produced in the city's wastewater treatment plant and the city buses ran on biogas, to an international market where biogas often is transported in the same way as fossil gas and marketed using the fossil gas together with certificates. The project "Renewable liquid biogas (LBG) for shipping in practice" was carried out by IVL Swedish Environmental Research Institute and RISE in 2023 together with stakeholders from the shipping sector, ports and industry organizations for biogas. The project has studied the conditions required to make LBG available to shipping in practice at Swedish ports. The study shows that the major obstacles to an established use of LBG in the shipping sector in Sweden today are pricing/willingness to pay that is affected by international market prices, lack of suitable logistical solutions as well as the absence of the piece of the puzzle that is the business model and cooperation needed to make available the large volumes of biogas that shipping may demand. The stakeholders in the project estimate their total need of biogas to 3 TWh in a short term, and 10 TWh in a longer term. The project has identified a number of conclusions and recommendations for future work, including that the potential for biogas is large and untapped, but that new solutions for the distribution and logistics of LBG are needed. There is a clear interest from maritime actors as they see biogas as a strategic solution and the dialog between actors in the industry remains important. A change in the tax system could be needed so that more actors can use the green gas principle for LBG. In addition, a functioning "marketplace" is needed, which simplifies for sellers and buyers of LBG, and agreements/contracts are needed that are longterm and to a greater extent based on the costs of producing and providing LBG.

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  • 37.
    Gypa, Ioli
    et al.
    Chalmers Tekniska Högskola, Sweden.
    Jansson, Marcus
    Kongsberg Maritime Sweden AB, Sweden.
    Gustafsson, Robert
    Kongsberg Maritime Sweden AB, Sweden.
    Werner, Sofia
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Bensow, Rickard
    Chalmers Tekniska Högskola, Sweden.
    Controllable-pitch propeller design process for a wind-powered car-carrier optimising for total energy consumption2023Ingår i: Ocean Engineering, ISSN 0029-8018, E-ISSN 1873-5258, Vol. 269, artikel-id 113426Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wind-powered ship propulsion (WPSP) is the concept where the wind is the main source of thrust, while the traditional propulsion system operates when needed. This type of propulsion can lead to considerably reduced emissions, something that the shipping community is striving for. A well-known example of WPSP is the Oceanbird with the goal to cut emissions of up to 90%. In this study, the propeller design process for a wind-powered car-carrier (wPCC) such as the Oceanbird is investigated, what the various challenges of WPSP are and therefore how an automated optimisation procedure should be approached. A controllable-pitch propeller was selected as suitable propeller type for the operation of the wPCC, and various functions such as windmilling, feathering and harvesting have been explored. Regarding the optimisation procedure, an essential input is the definition of the operational profile, in order to determine the most important conditions for the route. The main objective of the optimisation is the minimisation of the total energy consumption (TEC), calculated based on a selection of conditions using the potential flow solver MPUF-3A. Cavitation has been evaluated by the blade designer, through an interactive optimisation method. The results showed that designing and optimising for the most highly loaded condition led to solutions with the lowest TEC. © 2022 The Author(s)

  • 38.
    Gypa, Ioli
    et al.
    Chalmers University of Technology, Sweden.
    Jansson, Marcus
    Kongsberg Maritime Sweden AB, Sweden.
    Gustafsson, Robert
    Kongsberg Maritime Sweden AB, Sweden.
    Werner, Sofia
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Bensow, Rickard
    Chalmers University of Technology, Sweden.
    Propeller design procedure for a wind-assisted KVLCC22022Ingår i: PRADS 2022 Book of Abstracts, 2022Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wind-assisted ship propulsion (WASP) has received much attention lately with research focusing on the different sail technologies, ship-hull design optimisation and weather route optimisation. However, the traditional propulsion system is still needed for wind assisted vessels and is associated with several challenges, related to the wide range of operating conditions and propeller loads due to the varying degree of wind-assistance that will occur. In this study we use an interactive design and optimisation methodology applied on propellers of wind-assisted vessels. The methodology involves handling the complete operating profile of the propeller, an optimisation method for interactive cavi-tation evaluation by the blade designer, and the use of a new objective, the total energy consumption (TEC) of the expected operation. We use a case study where the KVLCC2 tanker is retrofitted with six Flettner rotor sails, operating between two fixed destinations at constant speed. The purpose is to investigate to what extent a new propeller design can offer a significantly lower TEC when compared to the existing design. Based on the results of this study, approximately 0.9% further reduction in TEC was achieved with the WASP adapted propeller compared to the existing one.

  • 39.
    Huang, Chen
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Temple, Alastair
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Ramachandra, Vasudev
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Anderson, Johan
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Andersson, Petra
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Modelling thermal runaway initiation and propagation for batteries in dwellings to evaluate tenability conditions2022Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Thermal propagation is one of the major challenges when batteries will be used in dwellings in large scale. It means the exothermic reactions in the cell are out of control and can lead to a fast release of flammable and toxic gases. In a system involving a large number of cells, thermal runaway can rapidly propagate from one battery cell to the whole system, which means substantial fire and explosion risks, an event that is important to mitigate and prevent. Multi-physics simulations together with full-scale testing is a cost-effective method for designing safer batteries. This project aims at simulating thermal runaway initiation and propagation using a multi-physics commercial software GT-Suite. 

    A battery thermal runaway model containing 12 prismatic cells based on 3-D Finite Element approach was built using GT-Suite. The computed thermal runaway time instants versus thermal runaway cell number were compared with full-scale experimental data with reasonable agreement. Quantitative sensitivity study on the model input parameters and model space and time resolutions on the computed start time instant and time duration of thermal runaway were performed. The thermal runaway model was then extended with an electric equivalent sub-model to simulate the short circuit. With the electrical model acting as the input to the thermal model, the most interesting output of the simulation is the change in temperature of the cells, dependent on the current in the cells, with respect to time. The current is determined by the value of the external resistance through which the short takes place and the voltage level of the battery pack. The obtained results from the above short circuit simulations can only be used as a starting point and not as absolute values for neither triggering the thermal model nor for accurately simulating a battery under an electrical load. Furthermore, GT-Suite was applied to simulate the gas dispersion inside a room. A comparative study of the dispersion of toxic gases during thermal runaway, utilising an arbitrary release of HCN to represent the battery gases, in a small compartment with natural ventilation was investigated and the results compared the same situation simulated in FDS. The pipe based modelling supported by GT-Suite has limited applicability and overestimated the concentrations close to the ceiling whereas the lateral concentrations where underestimated. 

    The multi-physics model for battery thermal runaway process is promising and worth to be applied with care for designing safer batteries in combination with full-scale testing. 

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  • 40.
    Hörteborn, Axel
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Chalmers University of Technology, Sweden.
    Allision modelling in IWRAP Mk II - A verification and sensitivity study2024Ingår i: Proceedings of the 9th International Conference on Collision and Grounding of Ships and Offshore Structures, ICCGS 2023, CRC Press/Balkema , 2024, s. 51-58Konferensbidrag (Refereegranskat)
    Abstract [en]

    Risk assessment is important both while planning to build new infrastructure and for maintenance of existing structures. The probability of ship-structure allisions could be estimated with IWRAP Mk II, which is a commonly used software for estimating maritime risks. However, the research coverage of the software is limited with regards to groundings and allisions. The aim of this study is to verify how IWRAP Mk II estimates the accident probability. To perform this verification a separate tool is constructed, OMRAT, based on the same theory as IWRAP Mk II. The aim is also to highlight the sensitivity of different parameters in these types of models. It is concluded that IWRAP Mk II estimates the probability of allisions and groundings with the same equations. Another conclusion is that some parameters have a linear effect on the accident probabilities and other parameters are also influenced by the model layout.

  • 41.
    Hörteborn, Axel
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Chalmers University of Technology, Sweden.
    Allision modelling in IWRAP Mk II – A verification and sensitivity study: Chapter 82023Ingår i: Advances in the Collision and Grounding of Ships and Offshore Structures: PROCEEDINGS OF THE 9th INTERNATIONAL CONFERENCE ON COLLISION AND GROUNDING OF SHIPS AND OFFSHORE STRUCTURES (ICCGS 2023), NANTES, FRANCE, 11-13 SEPTEMBER 2023, CRC Press, 2023, Vol. 12, s. 51-58Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Risk assessment is important both while planning to build new infrastructure and for maintenance of existing structures. The probability of ship-structure allisions could be estimated with IWRAP Mk II, which is a commonly used software for estimating maritime risks. However, the research coverage of the software is limited with regards to groundings and allisions. The aim of this study is to verify how IWRAP Mk II estimates the accident probability. To perform this verification a separate tool is constructed, OMRAT, based on the same theory as IWRAP Mk II. The aim is also to highlight the sensitivity of different parameters in these types of models. It is concluded that IWRAP Mk II estimates the probability of allisions and groundings with the same equations. Another conclusion is that some parameters have a linear effect on the accident probabilities and other parameters are also influenced by the model layout.

  • 42.
    Hörteborn, Axel
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Chalmers University of Technology, Sweden.
    Hassellöv, Ida-Maja
    Chalmers University of Technology, Sweden.
    Economic incentives and technological limitations govern environmental impact of LNG feeder vessels2023Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 429, artikel-id 139461Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the transition to sustainable shipping, Liquified Natural Gas (LNG), is proposed to play a role, reducing emissions of sulphur and nitrogen oxides, and particulate matter. However, LNG is a fossil fuel and there is an ongoing discussion regarding the extent of methane slip from ships operating on LNG, challenging the assumptions of LNG as a sustainable solution. Here we show another aspect to consider in the environmental assessment of shipping; LNG feeder vessels may spend as much as 25% of their time at sea just running the ship to ensure the pressure in the tanks are not exceeded, i.e., run time not directly attributed to the shipment of gas from one port or ship, to another. In other words, the economic incentives are currently allowing for roughly 32% increase of the ships’ operational emissions and discharges and increased navigational risks. Most coastal areas are heavily affected by anthropogenic activities and e.g., in the Baltic Sea there is consensus among the HELCOM member states that the input of nutrient and hazardous substances must be reduced. Even if the LNG feeder vessels are currently few, the possibility to reduce their environmental impact by 32% should be an attractive opportunity for future policy measures and investigation of technological solutions of the problem. 

  • 43.
    Hörteborn, Axel
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Chalmers University of Technology, Sweden.
    Ringsberg, Jonas W
    Chalmers University of Technology, Sweden.
    A method for risk analysis of ship collisions with stationary infrastructure using AIS data and a ship manoeuvring simulator2021Ingår i: Ocean Engineering, ISSN 0029-8018, E-ISSN 1873-5258, Vol. 235, artikel-id 109396Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The study presents a methodology that uses AIS data and a ship manoeuvring simulator to simulate and analyse marine traffic schemes with regard to risks for accidents. An event identification method is presented, which is needed for the accident scenario part of the methodology. This is based on AIS data, where the Great Belt VTS area was used to verify the methodology. Three events that could result in ship-bridge allisions were modelled and simulated in the simulator: drifting ship, sharp turning ship and miss of turning point. The Monte Carlo method was used to perform large number of simulator runs, including a parameter sensitivity analysis. The probability of a ship allision against the Great Belt Bridge was calculated to be 0.007. Analysis of the ship-bridge allision cases was shown to be dominated by the event drifting ship. This event has a relatively low kinetic energy at the impact, and the expected allision energy for a 1,000-year allision corresponds to a 178 m tanker with 57,870 DWT and ship speed 14.6 knots. Finally, this study presents a mitigation analysis, which shows how the probability of allisions can be reduced by reducing the ship speed or altering the traffic separation scheme. © 2021 The Authors

  • 44.
    Irannezhad, Mohsen
    et al.
    Chalmers University of Technology, Sweden.
    Bensow, Rickard E.
    Chalmers University of Technology, Sweden.
    Kjellberg, Martin
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Eslamdoost, Arash
    Chalmers University of Technology, Sweden.
    Comprehensive computational analysis of the impact of regular head waves on ship bare hull performance2023Ingår i: Ocean Engineering, ISSN 0029-8018, E-ISSN 1873-5258, Vol. 288, artikel-id 116049Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper focuses on investigating the impact of waves on ship hydrodynamic performance, enhancing our understanding of seakeeping characteristics and contributing to advanced ship and propeller design. It examines the resistance, motions, and nominal wake of the KVLCC2 bare hull, which is free to surge, heave, and pitch, in both calm water and regular head waves using a RANS approach. The research reveals a substantial dependency of the wake on grid resolution, particularly in calm water and shorter waves, while motions and resistance display a weaker dependency. The computed nominal wake is compared against towing tank SPIV measurements. Utilizing Fourier analyses and reconstructed time series, the study examines correlations among various factors influencing the bare hull’s performance in waves. The axial velocity component of the wake in waves demonstrates significant time variations, mainly driven by higher harmonic amplitudes. This dynamic wake is influenced by instantaneous propeller disk velocities due to hull motions, orbital wave velocities, boundary layer contraction/expansion, bilge vortex and shaft vortex dynamics. The wake distribution at the propeller plane not only differs significantly from the calm water wake in longer waves but also exhibits notably larger time-averaged values (up to 21%). 

  • 45.
    Irannezhad, Mohsen
    et al.
    Chalmers University of Technology, Sweden.
    Bensow, Rickard E
    Chalmers University of Technology, Sweden.
    Kjellberg, Martin
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Eslamdoost, Arash
    Chalmers University of Technology, Sweden.
    Towards Uncertainty Analysis of CFD Simulation of Ship Responses inRegular Head Waves2021Ingår i: Proceedings of the 23rd Numerical TowingTank Symposium, NuTTS 2021, 2021Konferensbidrag (Refereegranskat)
    Abstract [en]

    Ship hydrodynamic performance prediction in waves is a common practice in the early stages of the ship design process as the interaction between the ship and waves may adversely affect the hydrodynamic responses of the ship in comparison to calm water. Various well­established numerical and experimental methods are often utilized for prediction of ship performance in waves. Although the model tests are expensive and time­consuming, a high level of accuracy is often achieved in such experiments. On the other hand, with respect to the increased computational power, prediction of ship performance in waves by the numerical methods based on Computational Fluid Dynamics (CFD) techniques are gradually acquiring more popularity. However, the validity of the incorporated discretization schemes and modelling assumptions in these state­of­the­art CFD methods are often overlooked and the method accuracy is mainly assessed through the validation of the results based on the respective model test data. Validation as an engineering exercise aims to show that the right equations are solved, while verification (mathematical exercise) is required to demonstrate that equations are solved right [1]. The eventual objective of this research is to perform verification and validation exercises of a ship performance prediction in regular head waves using CFD, whereas in this paper, the working progress is presented which may be subjected to significant revisions. To this end, extensive attempts have been made to investigate numerical wave propagation without the presence of the hull. Ship responses in waves are significantly influenced by the wave excitation forces. Therefore, not only high level of accuracy is required for the simulation of the numerical waves, but also quantification of the numerical uncertainties are of a great importance. This becomes even more challenging when the ship hydrodynamic responses, such as motions and added resistance in waves, exhibit dependencies on wave steepness. In this paper, the main focus of such uncertainty analyses is on the systematic grid convergence study.

  • 46.
    Irannezhad, Mohsen
    et al.
    Chalmers University of Technology, Sweden.
    Eslamdoost, Arash
    Chalmers University of Technology, Sweden.
    Kjellberg, Martin
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Bensow, Rickard
    Chalmers University of Technology, Sweden.
    Investigation of ship responses in regular head waves through a Fully Nonlinear Potential Flow approach2022Ingår i: Ocean Engineering, ISSN 0029-8018, E-ISSN 1873-5258, Vol. 246, artikel-id 110410Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, the hydrodynamic performance of a ship in terms of motions and resistance responses in calm water and in regular head waves is investigated for two loading conditions using a Fully Nonlinear Potential Flow (FNPF) panel method. The main focus is understanding the ship responses in a broad range of operational conditions. Comprehensive analyses of the motions and their correlation with the wave making resistance including their harmonics in waves are presented and compared against experimental data. The predicted motions compare well with experimental data but the resistance prediction is not quite as good. The natural frequencies for heave and pitch are estimated from a set of free decay motion simulations in calm water to provide a better insight into the ship behavior near resonance conditions in waves. Interestingly, in addition to the well known peak in the added wave resistance coefficient around wave lengths close to one ship length, a secondary peak is detected in the vicinity of wave lengths with half the ship length. © 2022 The Authors

  • 47.
    Irannezhad, Mohsen
    et al.
    Chalmers University of Technology, Sweden.
    Kjellberg, Martin
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Bensow, Rickard E.
    Chalmers University of Technology, Sweden.
    Eslamdoost, Arash
    Chalmers University of Technology, Sweden.
    Experimental and numerical investigations of propeller open water characteristics in calm water and regular head waves2024Ingår i: Ocean Engineering, ISSN 0029-8018, E-ISSN 1873-5258, Vol. 302, artikel-id 117703Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Propeller Open Water (POW) performance of a non-ventilating and fully-submerged propeller in model-scale is investigated in calm water and regular head waves using experimental tests (EFD) and Computational Fluid Dynamics (CFD). Laminar flow dominance is observed in calm water, particularly at higher advance ratios. Nevertheless, the findings in waves suggest increased turbulence, stemming from both the wave orbital velocities and the presumably increased turbulence level produced by the wave maker in the towing tank. Analysis of the CFD results obtained from the incident flow field and single-blade force and moment leads to the speculation that the observed discrepancies are associated with the inevitable asymmetric conditions and mechanical interference in the experiments which were absent in CFD. These can potentially alter the flow over the blades resulting in a different flow transition, separation, and coherent turbulent structure formation and hence forces and moments. The altered propeller performance in waves in comparison to calm water underlines the significance of waves on the propulsive factors and propeller design. © 2024 The Authors

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  • 48.
    Johannes, Palm
    et al.
    Sigma Energy & Marine, Sweden.
    Eskilsson, Claes
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Verification and validation of MoodyMarine: A free simulation tool for modelling moored MRE devices2023Ingår i: Proceedings of the 15th European Wave and Tidal Energy Conference, 2023, Vol. 15, artikel-id 317Konferensbidrag (Refereegranskat)
    Abstract [en]

    This work presents the verification and validation of the freely available simulation tool MoodyMarine, developed to help meet some of the demands for early stage development of MRE devices. MoodyMarine extends the previously released mooring module MoodyCore (Discontinuous Galerkin Finite Elements) with linear radiation-diffraction bodies, integrated pre-processing workflows and a graphical user interface. It is a C++ implementation of finite element mooring dynamics and Cummins equations for floating bodies with weak nonlinear corrections. A newly developed nonlinear Froude-Krylov implementation is verified in the paper, and MoodyMarine is compared to CFD simulations for two complex structures: a slack-moored floating offshore wind turbine and a self-reacting point-absorber with hybrid mooring. 

  • 49.
    Jolak, Rodi
    et al.
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system. Gothenburg University, Sweden; Chalmers University of Technology, Sweden; Volvo Car Corporation, Sweden.
    Rosenstatter, Thomas
    RISE Research Institutes of Sweden, Digitala system, Mobilitet och system. RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen. Chalmers University of Technology, Sweden.
    Aldaghistani, Saif
    Chalmers University of Technology, Sweden.
    Scandariato, Riccardo
    Hamburg University of Technology, Germany.
    RIPOSTE: A Collaborative Cyber Attack Response Framework for Automotive Systems2022Konferensbidrag (Refereegranskat)
    Abstract [en]

    The automotive domain has got its own share of advancements in information and communication technology, providing more services and leading to more connectivity. However, more connectivity and openness raise cyber security and safety concerns. Indeed, services that depend on online connectivity can serve as entry points for attacks on different assets of the vehicle. This study explores collaborative ways of selecting response techniques to counter real-time cyber attacks on automotive systems. The aim is to mitigate the attacks more quickly than a single vehicle would be able to do, and increase the survivability chances of the collaborating vehicles. To achieve that, the design science research methodology is employed. As a result, we present RIPOSTE, a framework for collaborative real-time evaluation and selection of suitable response techniques when an attack is in progress. We evaluate the framework from a safety perspective by conducting a qualitative study involving domain experts. The proposed framework is deemed slightly unsafe, and insights into how to improve the overall safety of the framework are provided.

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  • 50.
    Kanchiralla, Fayas Malik
    et al.
    Chalmers University of Technology, Sweden.
    Brynolf, Selma
    Chalmers University of Technology, Sweden.
    Olsson, Tobias
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Ellis, Joanne
    RISE Research Institutes of Sweden, Säkerhet och transport, Maritima avdelningen.
    Hansson, Julia
    Chalmers University of Technology, Sweden; IVL Swedish Environmental Research Institute, Sweden.
    Grahn, Maria
    Chalmers University of Technology, Sweden.
    How do variations in ship operation impact the techno-economic feasibility and environmental performance of fossil-free fuels?: A life cycle study2023Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 350, artikel-id 121773Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Identifying an obvious non-fossil fuel solution for all ship types for meeting the greenhouse gas reduction target in shipping is challenging. This paper evaluates the technical viability, environmental impacts, and economic feasibility of different energy carriers for three case vessels of different ship types: a RoPax ferry, a tanker, and a service vessel. The energy carriers examined include battery-electric and three electro-fuels (hydrogen, methanol, and ammonia) which are used in combination with engines and fuel cells. Three methods are used: preliminary ship design feasibility, life cycle assessment, and life cycle costing. The results showed that battery-electric and compressed hydrogen options are not viable for some ships due to insufficient available onboard space for energy storage needed for the vessel’s operational range. The global warming reduction potential is shown to depend on the ship type. This reduction potential of assessed options changes also with changes in the carbon intensity of the electricity mix. Life cycle costing results shows that the use of ammonia and methanol in engines has the lowest life cycle cost for all studied case vessels. However, the higher energy conversion losses of these systems make them more vulnerable to fluctuations in the price of electricity. Also, these options have higher environmental impacts on categories like human toxicity, resource use (minerals and metals), and water use. Fuel cells and batteries are not as cost-competitive for the case vessels because of their higher upfront costs and shorter lifetimes. However, these alternatives are less expensive than alternatives with internal combustion engines in the case of higher utilization rates and fuel costs.

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