MODEL EQUATIONS OF NON-LINEAR ACOUSTICS

This paper is devoted to a strictly limited aspect of nonlinear acoustics - that of the numerous ″model equations″ that have now been derived to represent nonlinear sound propagation in various media and circumstances. It is the conflict between cumulative nonlinear distortion and the competing linear processes which it evokes that is described by the model equations reviewed here. The numerousness of these equations is due to the simple isotropic nondispersive scalar nature of the acoustic wave field subjected to nonlinear effects.