Propagation of finite amplitude acoustic waves in a two-dimensional rectangular duct

Finite amplitude acoustic waves (FAAWs) that propagate in a two-dimensional rectangular duct of semi-infinite length as a result of periodic excitatio n are determined by using second-order perturbation, based on the partial w ave analysis method. With second-harmonic boundary and initial conditions o f excitation, second-harmonic analytical expressions, which are applicable to quantitative analysis, have been derived. In this manner, a physical mec hanism of second-harmonic generation and propagation in the process of prop agation of FAAWs is clearly displayed. Based on the formula, some numerical calculations are performed. The numerical results clearly exhibit the dist ortion and symmetry of second-harmonic field pattern for a given source of excitation. (C) 1998 Academic Press.