Subgrid-scale contributions to Lagrangian time correlations in isotropic turbulence

• 来源期刊: 力学学报(英文版)
• 年，卷（期）: 2009,（1）
• 页码范围: 45-49
• 页数: 5页
• 语种: 英文
• DOI: 10.1007/s10409-008-0220-8

摘要

The application of large-eddy simulation (LES) to particle-laden turbulence raises such a fundamental ques-tion 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 investi-gated 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 car-ded 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.