Change search
ReferencesLink to record
Permanent link

Direct link
Drag and Wake Measurements on Cylinders and Discs for Wind Turbine Wake Modelling
Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, Department of Energy and Process Engineering.
2014 (English)MasteroppgaveStudent thesis
Abstract [en]

This master thesis presents an experimental study of the mean wake velocities, the drag coefficients and the vortex frequencies behind cylinders, porous discs and circular full discs. The thesis contributes to the development and better understanding of simple wind turbine wake models. The future long term goal is to improve the complex fluid flow models of wind turbines. The experimental trials were executed in two different wind tunnels at the Energy and Process Engineering Department of NTNU. The main trials have been conducted to determine the drag coefficient with two independent methods. Pitot tubes were used to determine the mean wake velocities and the drag coefficients by using the measurement by wake method. Furthermore, the force survey method was established by using a force plate. A broad literature survey revealed a consistent range of drag coefficients and mean wake velocities comparable to the determined results of the current investigation. Additionally it was found, that the measured upstream flow velocity has a major influence on the measurement by wake method. The results of the force survey method gave strong evidence, that the blockage effect has a negative influence. The final experiments were conducted as additional study on wake flows. The method applied was based on hot wire velocity measurements to determine the vortex shedding frequencies. A literature review predicted the vortex shedding frequencies of cylinders and circular full discs in a comparable range of the experimental results shown by the power spectral density analysis. The analysis of the porous biplane disc unfolded no discrete frequency. A comparison of the results of the mean wake flows revealed a significant variation between shape of the cylinder and discs to the model wind turbine. However, the porous monoplane disc achieved the best results and is therefore most promising for future investigations on wind turbine wake modelling.

Place, publisher, year, edition, pages
Institutt for energi- og prosessteknikk , 2014. , 85 p.
URN: urn:nbn:no:ntnu:diva-26563Local ID: ntnudaim:12088OAI: diva2:748589
Available from: 2014-09-19 Created: 2014-09-19 Last updated: 2014-09-19Bibliographically approved

Open Access in DiVA

fulltext(20334 kB)7808 downloads
File information
File name FULLTEXT01.pdfFile size 20334 kBChecksum SHA-512
Type fulltextMimetype application/pdf
cover(184 kB)1 downloads
File information
File name COVER01.pdfFile size 184 kBChecksum SHA-512
Type coverMimetype application/pdf

By organisation
Department of Energy and Process Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 7808 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 31 hits
ReferencesLink to record
Permanent link

Direct link