Effect of mean flow on mutual radiation resistances of a rectangular plate

Institute of Acoustics, Tongji University, Shanghai, 200092, China

^* Corresponding author: lpzhu@126.com

Abstract

Very few investigations have considered the effects of fluid convection on the mutual- radiation resistance, which could be important in stationary fluids. In this work, we quantified the effects of a convected fluid on the radiation resistances including self- and mutual radiation resistances. We derived the non-dimensional modal impedance in the presence of mean flow based on an expansion in the panel mode of a simply supported plate. Then we compared the self-radiation resistances with the previous reports and analyzed the effects of flow on mutual radiation resistances. The results show that the radiation efficiency increases with the flow velocity, which compare very well with the previous reports. The flow introduces a strong coupling between modes that weakly coupled in no-flow case and with the increase of flow velocity. This coupling effect increases until Mach number (M) reaches 0.5 and then decreases. For the modes with the same parity indices, the flow shifts coupling lobes toward lower frequency with the increase of flow velocity due to the shift of critical frequency of higher mode radiation resistance, and the degree of coupling change is consistent with the change of critical frequency of the higher mode self-radiation resistance.