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, i.e., 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.

I.B. Abbasov PhD, is a specialist in computer engineering, aerospace engineering, and industrial design at the Southern Federal University in Russia.  He has numerous publications to his credit, focusing on the use of mathematical modeling and high-level computer programming for practical applications, such as ocean exploration.

Introduction 1

1 Scattering of Nonlinear Interacting Plane Acoustic Waves by a Sphere 7

1.1 Review of Studies Dealing with the Scattering of Plane Acoustic Waves by a Sphere 7

1.2 Problem Statement 10

1.3 Solving via the Inhomogeneous Equation with the Successive Approximations Method 13

1.4 Investigation of Acoustic Field of Difference Frequency 16

1.5 Investigation of Acoustical Field of the Sum Frequency Wave 34

1.6 Investigation of Acoustical Field of the Second Harmonics 36

1.7 Experimental Investigation Scattering of the Field of Acoustic Parametric Antenna by a Hard Sphere 48

1.7.1 Experimental Setup and Metrological Support for the Experiment 48

1.7.2 Results of the Experiments 52

1.7.3 Analysis of Combined Scattering Diagrams of the Nonlinear Interacting Plane Acoustic Waves by a Hard Sphere 61

1.8 A Comparative Analysis of Assumption and Experimental Scattering Diagrams for Secondary Field Waves 65

1.9 Conclusion 68

2 Scattering of Nonlinear Interacting Plane Acoustic Waves by a Cylinder 71

2.1 Review of Plane Acoustic Waves Scattering by a Cylinder 71

2.2 Statement of Problem 75

2.3 Investigation of Acoustic Field of Difference Frequency 79

2.4 Investigation of Acoustic Field of Sum Frequency 93

2.5 Investigation of Acoustic Field of the Second Harmonic 96

2.6 Discussion and Comparison of Results 108

2.7 Conclusion 113

3 Research of the Scattering of Nonlinear Interacting Plane Acoustic Waves by an Elongated Spheroid 115

3.1 Review of Plane Acoustic Waves Scattering by an Elongated Spheroid 115

3.2 Wave problems in Elongated Spheroidal Coordinates 118

3.3 Statement of Problem 120

3.4 Investigation of the Acoustic Field of Difference Frequency Wave 124

3.5 Investigation of the Acoustic Field of Sum Frequency 142

3.6 Investigation of the Acoustic Field of Second Harmonics 148

3.7 Discussion and Comparison of Results 160

3.8 Conclusion 164

References 165

Index 173