Directivity pattern of parametrically generated acoustic waves

Summary The generation of down-converted frequency waves in the nonlinear propagation of acoustic waves is examined, in order to investigate the effects produced by the finiteness of the medium or of the media of interaction. Oscillations of the directivity patternsvs. the width of the media of interaction are set in evidence and related to resonance conditions of the medium cavity. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.