Hybrid LES-RANS method based on an explicit algebraic Reynolds stress model
Publication date
2008
Document type
Conference paper
Author
Editor
Peng, Shia-Hui
Haase, Werner
Organisational unit
Scopus ID
ISBN
ISSN
Conference
2nd Symposium on Hybrid RANS-LES Methods 2007
Series or journal
Notes on Numerical Fluid Mechanics and Multidisciplinary Design
Periodical volume
97
Book title
Advances in hybrid RANS-LES modelling : papers contributed to the 2007 Symposium of Hybrid RANS-LES Methods, Corfu, Greece, 17-18 June, 2007
First page
487
Last page
492
Part of the university bibliography
✅
Abstract
Although LES is a highly promising simulation technique, it still suffers from extremely large resources required for the resolution of the near-wall region, especially for high-Re flows. That is the main motivation for setting up hybrid LES-RANS methods. Whereas RANS suits reasonably well to attached boundary layers, requiring much less CPU-time and memory than LES, the latter is recommended for complex large-scale flow phenomena, which RANS often fails to predict correctly. Both characteristics are combined in hybrid LES-RANS methods to obtain an optimal solution at lower cost. Meanwhile a variety of different hybrid concepts were proposed including DES. In the present study a non-zonal approach based on two different but unique models is preferred. The predefinition of RANS and LES regions is avoided and a gradual transition between both methods takes place which weakens the problem of setting up an appropriate coupling strategy. The new hybrid LES-RANS approach relies on a one-equation model for the turbulent kinetic energy in both modes. At this phase the model is of linear type. In addition to this linear eddy-viscosity model (LEVM), an explicit algebraic Reynolds stress model (EARSM) is applied in the RANS mode in order to account for the Reynolds stress anisotropy. This insertion leads to a non-linear model. The linear version is used for comparison in order to emphasize the advantages of the non-linear formulation. Both model variants have been tested on the basis of the standard plane channel flow and the flow over a periodic arrangement of hills. © 2008 Springer-Verlag Berlin Heidelberg.
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