The Hydrodynamic Noise Reduction Effect of the Dimples on Airfoil Structure

The hydrodynamic noise is the main noise source of underwater vehicles at high velocity. In this paper, we have studied the noise reduction effect of dimples. The dimples are placed on the transition area of airfoil structure and the turbulent flow can be changed. The flow field has been calculated by the large eddy simulation. Then, the turbulent fluctuation pressure has been extracted for the sound field calculation as the source. The hydrodynamic noise has been calculated by the Lighthill’s acoustic analogy and the combination of finite element and infinite element method. We have investigated the noise reduction effect of different aspect-ratio and diameter of the dimple. The results show that the dimples can prevent the boundary layer separation and control the hydrodynamic noise of airfoil structure. The reduction effect of hydrodynamic noise can reach 7dB under the optimized parameter. The study in this paper can help broaden the visual for the control of the hydrodynamic noise for underwater vehicles.