Interaction of Three-Dimensional Protuberances with a Supersonic Turbulent Boundary Layer

A comprehensive computational fluid dynamics study of the surface-pressure fluctuations induced by a cylindrical protuberance in a supersonic turbulent boundary layer is presented. The effects of two important parameters on the surface-pressure fluctuations are investigated: protuberance height to boundary-layer thickness and surface curvature. The turbulent boundary layer is modeled using a hybrid Reynolds-averaged Navier-Stokes and large-eddy-simulation approach known as detached-eddy simulation. At first extensive comparisons to experimental data for the surface-pressure coefficient and the unsteady surface-pressure coefficient were performed. Results from our computational-fluid-dynamics computations compared well to the experimental data in the wake region downstream of the protuberance and in the vicinity of the protuberance at other locations. Increasing the protuberance height relative to the boundary-layer thickness resulted in higher sound-pressure levels on the surface. In addition, the surface-pressure fluctuation showed more coherence in the spanwise direction ahead of the protuberance and immediately downstream of it. Increasing the surface curvature lowered the sound-pressure levels on the surface and resulted in stretched coherent structures in the spanwise direction. Convection velocities of the turbulent structures increased away from the protuberance and were in agreement with published literature.