Numerical investigation of subsonic 2D/3D cavity flows

Description/Abstract

Numerical simulations of flows over a two-dimensional (2D) and a three-dimensional (3D) rectangular cavity are reported. The aim is to study the near field unsteady flow and its noise radiation. For this purpose, the Reynolds Averaged Navier-Stokes equations were solved with a 4th-order optimized pre-factored compact finite difference scheme for spatial derivatives and a 4- 6 alternating stage low-dissipation, low-dispersion Runge-Kutta scheme for time integration. The length to depth ratio of the cavity is 2 and the length to width ratio is 1. The simulations were performed at a Mach number of 0.4 and a Reynolds number of 60,000 based on the depth of
cavity. To compute the turbulent flow field, the Spalart-Allmaras one-equation turbulence model was employed with Detached Eddy Simulation (DES). The Ffowcs Williams-Hawkings equation
was solved to estimate the far field acoustic radiation. In both cases, the flow oscillations were found to follow the Rossiter flow model. In the 2D case, an upstream dominance of the acoustic radiation was observed. In contrast, the 3D computation showed strong sound radiations in the upstream direction and vertically above the cavity. The lateral radiation was found to be weaker.