NUMERICAL SIMULATIONS OF TRANSONIC FLOW ACOUSTIC RESONANCE IN CAVITY

Direct numerical simulations are used to investigate transonic flow acoustic resonance in an open cavity. The numerical scheme minimizes the errors due to dispersion and dissipation of acoustic waves, and resolves both the unsteady flow and radiated acoustic field. Implicit solution of the compressible Navier-Stokes equations is obtained using a compact high-order spacial differencing scheme, coupled with high-order implicit filters. Second order temporal accuracy is achieved using a timeimplicit approximately-factorization, and Newton-like subiterations. Computational results are presented at sequential times to show the vortical structure and shock waves at two transonic free stream Mach numbers. The corresponding acoustic response is presented for the pressure fluctuations and sound pressure level spectra near the rear bulkhead. Comparison of the computed discrete frequencies with Rossiter’s correlation indicates that the feedback mechanism, which induces selfsustained flow oscillations in the cavity is well captured.