Investigation on the flow-induced structure noise of a submerged cone-cylinder-hemisphere combined shell

The flow-induced structure noise of underwater vehicles is chiefly caused by the structural vibration under the excitation of turbulent fluctuating pressure, which involves the complex coupling relationship and energy transfer among flow, structure and sound. In this paper, a hybrid numerical method based on computational fluid dynamics (CFD) and computational acoustics (CA) is applied to simulate the flow-induced structure noise of a submerged cone-cylinder-hemisphere combined shell under turbulent excitation. Based on the principle of reverberation method, an experiment was carried out in a low-noise gravity water tunnel, and numerical results were compared with experimental data to validate efficiency and accuracy of the numerical method. It is found that the energy of flow-induced structure noise is mainly concentrated in the medium and low frequency range within 500 Hz. And the line-spectrum characteristics of radiated noise are consistent with the inherent vibration characteristics of the structure. The peak frequencies of the radiated noise spectrum curve correspond to the coupled modes of the structure, and its near-field distribution is greatly affected by the structural vibration characteristics. Fluctuating pressure and flow-induced structure noise characteristics of the cone-cylinder-hemisphere shell under different flow velocities are also compared, which provides meaningful guidance for the noise control of underwater vehicles.