Self-excited supersonic cavity flow instabilities as aerodynamic noise sources

A turbulent cavity flow at Mach 1.5 and 2.5 is modelled to study the flow instability and the associated aerodynamic noise generation. The short-time averaged Navier-Stokes equations, coupled with a ķ –ώ turbulence model, are solved to predict the large-scale time-dependent flow. Values of the cavity wall pressure, drag, streamwise velocity and density are in good agreement with past measurements and the results of other computations. The noise generation physics of the unsteady flow is addressed by estimating the noise source strength in a Lighthill acoustic analogy. The time-dependent flow predictions highlighted the upstream and downstream cavity edges as areas of large flow unsteadiness. The same areas are identified by the acoustic analogy as the dominant noise source regions in this flow.