The suppression of hydrodynamic noise from underwater cavities by the change of back wall chamfer

Abstract

When underwater vehicles are sailing, high hydrodynamic noise will be generated through the opening cavities due to the interaction of the surface and the fluids. In the paper, we had tested different forms of back wall chamfer by numerical calculation based on the method of large eddy simulation, to control the impact of the eddy and break the flow at the trailing edge of the cavity, which is with the dimension of 100mm wide, 120mm high and 100mm long. The angle and shape of the trailing edge chamfer are changed to control the flow of the cavity. We had also investigated the effect of hydrodynamic noise suppression through the simulation, which is based on the method of Lighthill’s acoustic analogy. The results show that the change of back wall chamfer can stabilize the movement of the eddies inside the cavity and reduce the fluctuation pressure at the trailing edge of the cavity. The suppression of flow-induced noise can be up to 5 dB, if the back-wall chamfer is with the airfoil surface and the angle of back wall chamfer is properly designed.