UC Davis

We report on progress made in improving the performance of the well-established wall-adapting local eddy-viscosity model in an important class of multiscale flows, namely, that of unsteady, massively separated flows at high Reynolds number. While this model succeeds in capturing the asymptotic near-wall behavior of the eddy viscosity that enters the formulation of the model for the sub-grid scale correlations, its performance in these flows has proved to be unsatisfactory due to high levels of dissipation leading to poor predictions in the separated wakes. We have sought to improve the performance of this model by combining it with another, the regularized variational multiscale model, which better represents the interactions that occur in multiscale flows. This combination, which was implemented in OpenFOAM, was validated against experimental data for the challenging case of vortex shedding from circular cylinders at the high Reynolds number. Distinct improvements over the original model were obtained.