Hybrid numerical prediction and experimental validation of hydrodynamic self-noise of the sonar acoustic window

The accurate and efficient calculation of the sonar hydrodynamic self-noise is an effective way to predict the sonar detection performance and optimise the acoustic design of a sonar acoustic-window. This paper proposes a hybrid numerical method using the finite element method and uncorrelated wall plane waves technique, and considers the coupling of the structural vibration of the sonar acoustic-window and the internal and external sound fields of the cavity to predict the hydrodynamic self-noise of an arbitrary shaped sonar acoustic-window excited by a turbulent boundary layer. A typical model of a rectangular cavity with an elastic plate on one side was considered. The auto spectrum density function of the coupled vibration velocity of the elastic plate and interior sound pressure inside the cavity subjected to TBL excitation were calculated and compared with the analytical solutions. The results show that the proposed method exhibited excellent computational precision and efficiency. To further illustrate the application of the proposed approach, a model of a local real-scale stiffened sonar acoustic-window was considered. The numerical results of the spectral level of the sonar acoustic-window vibration acceleration and interior sound pressure were in good agreement with the experimental results measured in a large cavitation channel.