FLOW SOURCES OF WALL PRESSURE FLUCTUATIONS RESOLVED BY DDES IN A REATTACHING FLOW REGION

Abstract

This paper is concerned with the analysis of the flow structures responsible for the wall pressure fluctuations predicted by DDES near a reattachment. To this aim, a simulation of the flow over a thick plate is considered. It observed that the linear part of sources is dominant upstream of the reattachment, and that quadratic sources dominate downstream. This is associated with the rapid loss of coherence of the vortices shed from the separated shear layer in the downstream region. Furthermore, it is shown that linear stochastic estimation of the velocity field from the wall pressure well reproduce the linear sources, with negligible quadratic sources.