Finite element implementation of large eddy simulation for separated flows

摘要

In this paper, a finite element method is applied to the large eddy simulation of unsteady, vortex-shedding flows past a square cylinder. Galerkin FEM with linear, isoparametric elements is implemented. Unsteady computations are performed using the explicit (Euler) method, with a streamline upwind scheme for advection term. Subcycling strategy is incorporated into time integration. First, the results for two-dimensional, low Reynolds number flow with vortex shedding are presented to validate the computational methodology. Then, three-dimensional calculation of a flow past a square cylinder at Re = 22 000 is discussed. The Smagorinsky model is used for parametrization of the subgrid scales. No-slip wall condition is enforced. The computed mean and root mean square of pressure as well as wake structure are compared with numerical and experimental results reported by other researchers.