Wednesday, September 19, 1984 12:00 p.m.
Professor Mark F. Hamilton
Department of Mechanical Engineering
The University of Texas at Austin
Finite amplitude propagation of directional sound beams is well modeled by Kuznetsov’s paraxial wave equation, which accounts consistently for nonlinearity, diffraction, and absorption. The solution of Kuznetsov’s equation is found in the form of a Fourier series expansion, and the resulting coupled equations in the harmonic amplitudes are integrated numerically. Excellent agreement between theory and experiment will be presented for axial propagation curves and farfield beam patterns. Nearfield effects resulting in the splitting of sidelobes (the appearance of so-called fingers) in the harmonic beam patterns will be discussed. The numerical method also lends itself nicely to describing reflection of finite amplitude beams, for example from both finite and infinite pressure release surfaces.