Actuator line simulations of a Joukowsky and Tjaereborg rotor using spectral element and finite volume methodsVisa övriga samt affilieringar
2016 (Engelska)Ingår i: SCIENCE OF MAKING TORQUE FROM WIND (TORQUE 2016), 2016, artikel-id 082011Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]
The wake structure behind a wind turbine, generated by the spectral element code Nek5000, is compared with that from the finite volume code EllipSys3D. The wind turbine blades are modeled using the actuator line method. We conduct the comparison on two different setups. One is based on an idealized rotor approximation with constant circulation imposed along the blades corresponding to Glauert's optimal operating condition, and the other is the Tjareborg wind turbine. The focus lies on analyzing the differences in the wake structures entailed by the different codes and corresponding setups. The comparisons show good agreement for the defining parameters of the wake such as the wake expansion, helix pitch and circulation of the helical vortices. Differences can be related to the lower numerical dissipation in Nek5000 and to the domain differences at the rotor center. At comparable resolution Nek5000 yields more accurate results. It is observed that in the spectral element method the helical vortices, both at the tip and root of the actuator lines, retain their initial swirl velocity distribution for a longer distance in the near wake. This results in a lower vortex core growth and larger maximum vorticity along the wake. Additionally, it is observed that the break down process of the spiral tip vortices is significantly different between the two methods, with vortex merging occurring immediately after the onset of instability in the finite volume code, while Nek5000 simulations exhibit a 2-3 radii period of vortex pairing before merging.
Ort, förlag, år, upplaga, sidor
2016. artikel-id 082011
Serie
Journal of Physics Conference Series, ISSN 1742-6588, E-ISSN 1742-6596 ; 753
Nationell ämneskategori
Strömningsmekanik och akustik
Identifikatorer
URN: urn:nbn:se:uu:diva-400867DOI: 10.1088/1742-6596/753/8/082011ISI: 000436325702068OAI: oai:DiVA.org:uu-400867DiVA, id: diva2:1382603
Konferens
Conference on Science of Making Torque from Wind (TORQUE), OCT 05-07, 2016, Munich, GERMANY
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