Impact of dynamic subgrid-scale modeling in variational multiscale large-eddy simulation of bluff-body flows

Abstract

The effects of dynamic subgrid-scale (SGS) modeling are investigated in variational multiscale (VMS) large-eddy simulation (LES) simulations of bluff-body flows. The spatial discretization is based on a mixed finite-element/finite-volume formulation on unstructured grids. In the VMS approach used in this work, the separation between the largest and the smallest resolved scales is obtained through a variational projection operator and a finite-volume cell agglomeration. The dynamic and non-dynamic versions of Smagorinsky and wall-adapted local eddy-viscosity SGS models are used to account for the effects of the unresolved scales. In the VMS approach, these effects are only modeled in the smallest resolved scales. The VMS-LES and classical LES approaches, combined with the considered dynamic and non-dynamic SGS models, are applied to the simulation of the flow around a circular cylinder at Reynolds numbers 3,900 and 20,000 and to the flow around a square cylinder at Reynolds numbers 22,000 and 175,000.