Subgrid-scale contributions to Lagrangian time correlations in isotropic turbulence  

作　　者：Jian Zhang Guowei He Lipeng Lu 

机构地区：[1]LNM, Institute of Mechanics Chinese Academy of Sciences.100190 Beijing, China [2]National Key Laboratory for Aircraft Engines,Beihang University, 100191 Beijing, China

出　　处：《Acta Mechanica Sinica》2009年第1期45-49,共5页力学学报（英文版）

基　　金：the Chinese Academy of Sciences under the Innovative Project"Multi-scale modeling and simulation in complex Systems" (KJCX-SW-L08);the National Basic Research Program of China (973 Program) (2007CB814800); the National Natural Science Foundation of China (10325211, 10628206,10732090 and 10672012)

摘　　要：The application of large-eddy simulation （LES） to particle-laden turbulence raises such a fundamental question as whether the LES with a subgrid scale （SGS） model can correctly predict Lagrangian time correlations （LTCs）. Most of the currently existing SGS models are constructed based on the energy budget equations. Therefore, they are able to correctly predict energy spectra, but they may not ensure the correct prediction on the LTCs. Previous researches investigated the effect of the SGS modeling on the Eulerian time correlations. This paper is devoted to study the LTCs in LES. A direct numerical simulation （DNS） and the LES with a spectral eddy viscosity model are performed for isotropic turbulence and the LTCs are calculated using the passive vector method. Both a priori and a posteriori tests are carried out. It is observed that the subgrid;scale contributions to the LTCs cannot be simply ignored and the LES overpredicts the LTCs than the DNS. It is concluded from the straining hypothesis that an accurate prediction of enstrophy spectra is most critical to the prediction of the LTCs.The application of large-eddy simulation （LES） to particle-laden turbulence raises such a fundamental question as whether the LES with a subgrid scale （SGS） model can correctly predict Lagrangian time correlations （LTCs）. Most of the currently existing SGS models are constructed based on the energy budget equations. Therefore, they are able to correctly predict energy spectra, but they may not ensure the correct prediction on the LTCs. Previous researches investigated the effect of the SGS modeling on the Eulerian time correlations. This paper is devoted to study the LTCs in LES. A direct numerical simulation （DNS） and the LES with a spectral eddy viscosity model are performed for isotropic turbulence and the LTCs are calculated using the passive vector method. Both a priori and a posteriori tests are carried out. It is observed that the subgrid;scale contributions to the LTCs cannot be simply ignored and the LES overpredicts the LTCs than the DNS. It is concluded from the straining hypothesis that an accurate prediction of enstrophy spectra is most critical to the prediction of the LTCs.

关 键 词：Isotropic turbulence Large eddy simulation Lagrangian time correlation Enstrophy spectra 

分 类 号：O3[理学—力学]