Effect Of Acoustic Scattering From Curved Baffle On Direction-Finding Of Vector Hydrophone

With the development of vector hydrophone technology, vector hydrophone has been widely applied to almost every area of underwater acoustics. It has many advantages such as good directivity at low frequency and strong ability to immunize isotropic noise and can provides new ideas and methods for solving practical underwater acoustic engineering problems. However, as a novel technology, vector hydrophone fundamental physics theory is still required to be thoroughly studied.In this thesis, First, by physical acoustic method and near-field planar element method(PEM), a numerical method is established to calculate the scattering velocity potential of a rigid curved-surface baffle; the divergence problem of the results obtained by near-field PEM, introduced by the inexactness of the Fourier transform of a polygonal shape function, is discussed and a revised transform is derived and validated; numerical calculation of the sound pressure and particle velocity in the near field of the baffle is obtained and validated compared with the modal method; the influence of the near-field sound scattering of underwater platform on vector hydrophone's target bearing finding performance is studied by taking a rigid column with hemisphere on each side as the model, when the incident wave frequency and the incident angle and the installation position of hydrophone are changed.A numerical method, called FEM(Finite Element Method) + BEM(Boundary Element Method), which is used to analyze a elastic curved-surface baffle's sound scattering characteristic and its influence on vector hydrophone's direction finding. ANSYS is used to model a elastic curved-surface baffle and pick-up its topology, SYSNOISE is used to calculate the sound pressure and particle velocity in the near field of a elastic curved-surface baffle; The expressions of sound vector field of the scattering and transmission of plane wave on spherical shell, compared with which, FEM + BEM is validated; otherwise, the influence of the near-field sound scattering of a elastic sphere shell baffle and complex column shell baffle on sound wave receiving responses and receiving directivity diagram of the vector hydrophone and its target direction finding performance is studied, which may supply some theoretical foundation to vector hydrophone's installation on underwater platform and signal processing.