Statistics of confined turbulent flows with and without rotation effects

Abstract

A volume penalization method is implemented in a tri-periodic pseudo-spectral code. The numerical stability constraint of the method is studied and released with an original implicit formulation of the penalization term. The accuracy of the method in representing no-slip boundaries is tested by considering the impact of a three-dimensional vortex ring on a wall. This technique is then used to assess the influence of cylindrical boundaries on turbulent flow fields and on their structure at given radial positions. The Lagrangian study shows that the axial direction of the open-ends cylinder is privileged for the orientation of the turbulent structures. After these cases in which kinetic energy decays, we finally test rotating the outer cylindrical walls to force "naturally" the flow towards kinetic energy statistical equilibrim.