THE EFFECT OF TIME ACCURACY ON AN UNSTEADY ADVECTION BENCHMARK

摘要

Modeling strongly convective flows is one of the most difficult problems in Computational Fluid Dynamics (CFD). Many studies have focused on comparing the ability of different schemes to minimize both diffusion and dispersion in the presence of steep gradients without paying much attention to temporal discretization effects. In this paper, several different upwinding schemes are tested on the benchmark problem of the advection of a square pulse focusing on time accuracy. It is shown that of those methods tested, a third-order upwinding method known as Extended Linear Upwind Differencing (ELUD) is the best scheme for preserving the shape of the pulse. It is also shown that time accuracy has a significant effect on the ability of the overall scheme to preserve the shape of the pulse, regardless of which spatial scheme is used to discretize the convective terms.