Hyrdoacoustic Ocean Exploration

The only book that offers a comprehensive and fully up-to-date coverage of hydroacoustic ocean exploration, this work deals with the diagnostics of non-uniformities in a water medium using the hydroacoustic parametric antenna. The non-uniformities of the water medium in the study are of geometrically regular shape, id est, the shape of a sphere, a cylinder, and a spheroid. An account is given of theoretical and experimental studies of wave processes that occur in the event of the scattering of non-linearly interacting acoustic waves at a sphere, a cylinder, and a spheroid. Scattering problems are formulated; solutions to the inhomogeneous wave equation are found in the first and second approximations using the successive approximations method. For the first time, high-frequency asymptotic expressions of acoustic pressure for all spectral components of the secondary field are obtained for the nonlinear scattering problem. The scattering diagrams are calculated and plotted, and then analyzed and compared. Results of experimental studies of the parametric acoustic antenna field scattering at solid steel spheres are presented. Experimental scattering diagrams both for the parametric antenna pump waves and for the secondary field waves including the difference frequency wave, the sum frequency wave, and the second harmonic wave are presented. 3D modeling of wave processes is also considered. A must have for researchers and specialists in nonlinear hydroacoustics and ocean acoustics; it also may be of use for postgraduates and students specializing in hydroacoustics and ocean exploration.