HARMONIC-GENERATION IN PLANE AND CYLINDRICAL NONLINEAR RAYLEIGH-WAVES

Harmonic generation in plane and cylindrical nonlinear Rayleigh waves is investigated theoretically on the basis of spectral model equations for propagation in isotropic solids [E. A. Zabolotskaya, J. Acoust. Soc. Am. 91, 2569-2575 (1992)]. Approximate expressions are derived for second harmonic generation and for finite amplitude attenuation of the source frequency component. The expression for the source frequency component is in good agreement with numerical solutions of the model equations, even throughout the shock wave region. Acoustic saturation of both plane and cylindrical waves is predicted for sufficiently high source amplitudes, at which the amplitude of the Rayleigh wave at a given field point becomes independent of the source amplitude. Frequency spectra and time waveforms are calculated, and the spatial redistribution of the energy density due to harmonic generation is examined.