Numerical Modelling of some Problems in Nonlinear Acoustics

Abstract

Some recent developments in numerical nonlinear acoustics are presented. First a three dimensional perturbation approach based on the finite-element method is described. This procedure can predict the propagation of acoustic fields produced by sources of arbitrary geometry as well as the pressure distribution inside a three dimensional cavity including boundary layer absorption. Its main limitation is due to its range of validity limited to waves of finite but moderate amplitude. We then describe a second approach: a numerical model for nonlinear waves and weak shocks in thermoviscous fluids based in a time-domain finite-difference algorithm. This algorithm does not present any practical limitations about the amplitude of the wave but it is referred to one-dimensional problems. Some future trends are also commented.