A dynamic variational multiscale method for large eddy simulations on unstructured meshes

Abstract

A dynamic version of the variational multiscale (VMS) method for large eddy simulation (LES) on unstructured meshes of turbulent compressible flows is presented. Its key features include two variational analogues of Germano’s algebraic identity, and a computationally efficient, agglomeration-based numerical procedure. Agglomeration is used both for separating a priori the scales and computing dynamically a Smagorinsky parameter and the turbulent Prandtl number on unstructured finite volume or finite element meshes. Numerical predictions of low-speed, 20° angle of attack, turbulent flows past a 6:1 prolate spheroid and a forward swept scaled wing are presented. They are contrasted with counterpart results obtained using similar implementations on unstructured meshes of the VMS-LES, traditional LES, and traditional dynamic LES methods. They are also compared to experimental data when available.