Delayed detached-eddy simulation around NREL S826 blade section for transition prediction

2018-09-20
Yalçın, Özgür
Özyörük, Yusuf
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This proposed study aims at simulating slightly separated flow over the NREL S826 wind turbine blade section profile with delayed detached-eddy simulation (DDES) strategy. The Reynolds number is relatively low and the angles of attack are around the stall region so that flow is not massively detached. This kind of flow where laminar-turbulent transition and laminar separation take place is difficult to simulate by DDES. To handle the problem and increase the capability of DDES, three developments that appeared in literature only recently are combined. The first of these developments is a modification to Spalart-Allmaras (S-A) one equation, which allows setting initial eddy viscosity value as zero for apparent transition behavior and is selected as a turbulence model. Secondly, the shear-layer-adapted subgrid length scale instead of the classical one, maximum edge length of cells, is used in the resolved mode of DDES. By this enhancement, emergence of turbulent content could be accelerated inside boundary layers in case of instability. The third one is about adaptation of Bas-Cakmakcioglu (B-C) algebraic transition model to the modified S-A turbulence equation. The B-C model multiplies simply an intermittency function depending on local turbulent information with the production term of the S-A model, and thereby provides a boundary layer transition prediction. The ongoing simulations are being performed by an inhouse solver, METUDES, developed for aeroacoustic purposes. The solver features low dissipation, low dispersion with fourth-order accuracy which could also be beneficial in preserving instabilities during transition process. In the extended abstract, the aerodynamic results will be compared with those of available data from a DDES study that uses standard subgrid length scale, and from a RANS study that employs Langtry-Menter transition prediction model.
https://hdl.handle.net/11511/75389
https://phd2018.eawe.eu/site-phd2018/assets/files/download/Book_Of_Abstracts_Final.pdf
14th EAWE PhD Seminar, (18 - 20 Eylül 2018)
Department of Aerospace Engineering, Conference / Seminar

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Citation Formats
Ö. Yalçın and Y. Özyörük, “Delayed detached-eddy simulation around NREL S826 blade section for transition prediction,” Brüksel, Belçika, 2018, p. 31, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/75389.
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