Anisotropic Grid Refinement Study for LES

In this paper an anisotropic grid refinement study is proposed for use in Large-Eddy Simulation. The aim of the method is to compare the effect of different grid refinements. These refinements can be selected systematically in order to fit the grid to the anisotropy of the turbulence. Furthermore it is proposed that the results be compared using multiple objectives, i.e. to separate the effects on the different components of the Reynolds stress tensor. It was attempted to apply the Index of Resolution Quality for quantifying the various refinements. The method was applied to a spatially developing axisymmetric shear layer (round jet). Reynolds stresses, momentum thickness and vortices were plotted for this purpose. The results indicate that grid refinement in different directions has an effect differing both in manner and magnitude. This differing manner is highlighted in the various behaviours of the Reynolds stress components. The index of resolution quality was found to be misleading, since it can underestimate the relative importance of the grid refinement effects.