On the Role of an Anisotropy-Resolving Extra Term for a Subgrid-Scale Model in Near-Wall Turbulence

Abstract

Copyright © 2013 by JSME Abstract An anisotropy-resolving subgrid-scale (SGS) model for large eddy simulation was investigated. This SGS model is constructed by combining an isotropic linear eddyviscosity model with an extra anisotropic term. Although the basic performance of this model was validated by application to fundamental test cases, there still remain several points to be further investigated. In particular, it had not been made clear how the extra anisotropic term worked for improving the predictive performance under a coarse gridresolution condition. For this purpose, we investigated in detail the predicted turbulent structures in the near-wall region. In this study, primary attention was given to the role of the extra anisotropic term in the model. By comparison of the results obtained with and without this extra anisotropic term, it was found that this term was generally effective to enhance unsteady motions of vortex structures generated in the near-wall region. These motions are thought to increase the Reynolds shear stress, resulting in the improvement of the prediction accuracy.