Noise Radiated by an Open Cavity at Low Mach Number

Abstract

The present work focuses on the study of noise generation and radiation of unsteady laminar flow over an open three dimensional cavity at low Mach number, that is of interest to understand noise generation mechanisms in wall-bounded separated flows. The length to depth ratio of the cavity is L/D=4. While this configuration has been extensively studied, most of the works assume the flow to be two-dimensional. However, as it will be shown, previous studies confirm that for Reynolds numbers above ˜ 1200, the flow shows a three dimensional behaviour. This results in significantly different sound sources. This paper presents results of sound calculation radiated by a three-dimensional infinite open cavity at Reynolds number based on the cavity depth of Re = 1500 and Mach number of M= 0.15. To do so, two approaches have been used: Curle integral, evaluated as a post-process of an incompressible solution and compressible direct simulation. The results are also compared with the resulting Curle post-process of a two- dimensional incompressible simulation assumed to be constant along the spanwise direction.