Generation of acoustic disturbances in supersonic laminar cavity flows

The generation of acoustic disturbances in supersonic laminar cavity flows is investigated by large-eddy simulations of supersonic laminar flow (M = 1:2, 2:0, and 3:0) past a rectangular cavity with a length-To-depth ratio of 2. Results suggest that well-originated large-scale vortical structures with strong spanwise coherence are present in the shear layer. Compressibility effects have significant impacts on the shear-layer development and the fluctuation properties. The dominant mechanism for the acoustic radiation in supersonic laminar cavity flows is shown to be associated with the successive passage of large-scale vortices over the cavity trailing edge. It is found that Mach waves radiated from the cavity shear layer may have significant contributions for the noiseradiation in terms of enhancing the strength of the feedback compression waves.