Control of Acoustic Resonance in Shallow Rectangular Cavities Using Surface Mounted Blocks

摘要

Flow over cavities has been identified as a potential source of acoustic resonance in many engineering applications [1, 2]. The inherent instability of the shear layer over a cavity can give rise to pressure oscillations. A feedback mechanism can result in sustained oscillations in the flow field [3]. The oscillations of the shear layer at the cavity edge cause an oscillating mode at frequencies determined by, St_n = f_nl/U = 0.5n, n = 0, 1. 2,..., where l is the characteristic shear-layer length. St_n is the Strouhal number corresponding to the frequency f of the n~(th) mode at a flow velocity U [4].