39 / 2021-03-25 23:28:39

Near-field Acoustic Holography based on Prolate Spheroidal Wave Superposition

Near-field Acoustic Holography; Prolate Spheroidal waves; Wave Superposition; Underwater Vehicle

Vibro-acoustics and Structure-borne Noise

In this paper, a novel near-field acoustic holography based on prolate spheroidal wave superposition is presented to reconstruct the vibro-acoustic quantities of an underwater vehicle with large aspect ratio. Firstly, a set of transducer array mounted on an enclosed holographic surface are utilized to collect complex acoustic pressure of the sound radiation field. Then, the measured pressure is expanded by a series of complete and orthogonal prolate spheroidal waves, whose expansion coefficients are solved by data matching on the holographic surface. Next, the expansion coefficients are employed to establish a transfer matrix between measured pressure and reconstructed acoustic quantities. At last, the vibro-acoustic quantities across entire three-dimensional space can be reconstructed and visualized. In addition, Tikhonov regularization and generalized cross validation is usually involved to suppress the noise effects, as well as improve the accuracy of reconstruction results. Numerical simulations with a complex underwater vehicle model are carried out to validate the effectiveness and the feasibility of the proposed method. It is shown that the proposed method can achieve a great performance on acoustic field reconstruction of the underwater vehicle with less measurements and higher calculation speed. And the reliability is also confirmed by analysing reconstruction errors in a noisy environment.