Low-frequency hydrodynamic noise calculation of underwater vehicle with sparse grid conditions

A computational model of the acoustic vibration response of complex structures excited by pressure fluctuations in the turbulent boundary layer is constructed by combining the structural finite element method, the acoustic finite element method, and non-reflecting boundary conditions. The issue associated with the mesh size of the finite element model and the spatial correlation scale of the pressure fluctuations in the turbulent boundary layer is solved by introducing the virtual grid refinement to accomplish the correction of the uncorrelated flow excitation loads. The underwater vehicle’s low-frequency hydrodynamic noise calculation is carried out under sparse grid settings that meet the demands of the acoustic vibration response. The typical underwater rotary vehicle model is used as an example to calculate its low-frequency hydrodynamic radiation noise. When compared to the results of the discrete subunit method calculation and the large cavitation channel test, the three results are generally consistent, with the deviation of the results in the overlapping frequency range being less than 3 dB. The method is highly applicable and takes into account calculating efficiency and accuracy.