Семинар по аэромеханике

DNS of Turbulent Flow Around a Wall-Mounted Cube: Spatio-Temporal Evolution of Large-Scale Vortices

Alexander Yakhot*
Department of Mechanical Engineering
Ben-Gurion University, Beersheva 84105, Israel


The considered flow is an example of turbulent flows around a three-dimensional bluff body attached to a surface. The main experimentally observed feature of such flows is appearance of complex vortical structures, e.g. a horseshoe vortex, originated in front of a body and enveloping it. The unsteadiness of the turbulent flow around a wall-mounted cube is caused by a horseshoe vortex. In our recent direct numerical simulation (DNS) (A. Yakhot, H. Liu, N. Nikitin, “Turbulent Flow Around a Wall-Mounted Cube: a Direct Numerical Simulation, to appear in International Journal of Heat and Fluid Flow), the negative turbulence production is predicted in the region in front of the cube. In this study, we present details on spatio-temporal evolution of large-scale vortical structures, including long-term visualizations and turbulence statistics. Our results demonstrate that a horseshoe vortex around a wall-mounted cube is a chaotic large-scale unsteady structure that explains why the Reynolds-averaged closure models failed to predict global characteristics of that flow.

*)currently on sabbatical leave at: Division of Applied Mathematics, Brown University, Providence, RI 02912, USA