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ACCURACY OF SUBFILTER-SCALE MODELS FOR EXPLICIT FILTER LARGE-EDDY SIMULATION IN TURBULENT CHANNEL FLOW

Satbir Singh
Department of Mechanical Engineering Carnegie Mellon University Pittsburgh, Pennsylvania 15213, USA

Sanjeeb T. Bose
Department of Mechanical Engineering Stanford University Stanford, California 94305, USA

Donghyun You
Department of Mechanical Engineering, Carnegie Mellon University 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, USA

Аннотация

Large-eddy simulations (LES) of turbulent channel flow at Reτ = 395 are performed using explicit filtering. Three different subfilter-scale models: the dynamic Smagorinsky model of Germano et al. (1991), the dynamic global coefficient model of You & Moin (2007), and the dynamic Smagorinsky mixed model of Zang et al. (1993) are modified in accordance with explicitly-filtered LES governing equations. Explicit filtering separates the filtering operation, and hence the resolved turbulence, from the underlying grid resolution alleviating some of the grid sensitivities of LES solutions. Compared to the dynamic global-coefficient model, the dynamic Smagorinsky model is found to better agree with the filtered DNS on a coarse LES resolution. As the LES resolution is refined, the solution obtained using the dynamic global-coefficient model converges faster to the filtered DNS solution than that produced by the dynamic Smagorinsky model. The dynamic Smagorinsky mixed model is found to be superior to other compared models in predicting turbulence intensities.