SIMPLE CALCULATION APPROACH FOR THE 2ND-HARMONIC SOUND FIELD GENERATED BY AN ARBITRARY AXIAL-SYMMETRICAL SOURCE

In a linear approximation, an arbitrary axial-symmetric source can be expressed as the linear superposition of a set of Gaussian sources and the corresponding radiated sound held can be represented as the super position of this set of Gaussian beams. The analysis is extended to th e second harmonic generation due to nonlinear effects under a quasilin ear approximation, then the second harmonic sound field could be consi dered as a sum of self- and cross-interaction terms produced by a seri es of Gaussian beams. Therefore, the calculation of the second harmoni c sound field of an axial-symmetric source can be reduced to a simple linear combination of a set of exponential integral functions, instead of a complicated triple integral. In order to verify this calculation approach, the second harmonic generation of a focused and a simple pi ston source is examined, and the result is in good agreement with that in earlier paper by complicated computation. (C) 1996 Acoustical Soci ety of America.