Approximation of subgrid-scale stresses based on the Leonard expansion
2009 (English)In: Turbulence, Heat and Mass Transfer 6 / [ed] K. Hanjali´c, Y. Nagano and S. Jakirli´c, 2009Conference paper (Refereed)
Based on the reconstruction series for subgrid-scale (SGS) stress tensor, SGS modellingis revisited. It is shown that, along with the first Leonard term in the series, the second term is alsoexploitable in relation to the viscous dissipation rate tensor, "ij , being further subjected to a Leonardexpansion. The approximation of "ij is discussed in analogy to RANS modelling. With the assumptionof anisotropy dissipation, it is shown that the second term can be approximated in terms of an eddyviscosityformulation, which, together with the first Leonard term, forms a two-term mixed model. Theresulting mixed model has been analyzed in LES of turbulent channel flow. The emphasis in the presentwork has been placed on the effect of model coefficients. The Leonard term may induce negative diffusionassociated to energy backscatter, while the second Smagorinsky term reinforces energy dissipation.Moreover, the modelled Leonard stresses have also been highlighted in the computation.
Place, publisher, year, edition, pages
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-85622DOI: 10.1615/ICHMT.2009.TurbulHeatMassTransf.1410OAI: oai:DiVA.org:kth-85622DiVA: diva2:500087
6th International Symposium on Turbulence, Heat and Mass Transfer. Rome, Italy. September 14-18, 2009
QC 201204262012-02-132012-02-132012-04-26Bibliographically approved