Vortex sound interaction in acoustic resonance of a flow duct containing a plate

Abstract

Acoustic resonance induced by vortex shedding from a flat plate in a flow duct has been widely concerned in a variety of engineering applications. However, the unsteady vortex sound interaction is still an open issue. A nonlinear physical model is established based on three meshless sub-models, including the discrete vortex method (DVM) for vortex shedding, the vortex sound theory for sound radiation and the time-domain boundary element method (TDBEM) for sound propagation within the duct. Then, the feedback effect of sound wave is considered by adding acoustic particle velocity onto the potential flow of vortex shedding, which makes the coupling process bidirectional. Both the flow field, sound field and their unsteady interaction are obtained simultaneously. The predicted resonant frequency and amplitude results are in accordance with the previous experiment data, especially, the lock-in phenomenon is reasonably captured. By comparing the numerical results with and without acoustic feedback, it reveals that the feedback sound plays a significant role in the onset of lock-in phenomenon, including enhancing the strength and modulating the frequency of vortex shedding. It helps to get a more detailed insight into the underlying physical process of vortex sound interaction for studying control strategy.