Index of content:
Volume 113, Issue 2, February 2003
- NONLINEAR ACOUSTICS 
Nonlinear scattering of acoustic waves by natural and artificially generated subsurface bubble layers in sea113(2003); http://dx.doi.org/10.1121/1.1526497View Description Hide Description
The paper describes nonlinear effects due to a biharmonic acoustic signalscattering from air bubbles in the sea. The results of field experiments in a shallow sea are presented. Two waves radiated at frequencies 30 and 31–37 kHz generatedbackscattered signals at sum and difference frequencies in a bubble layer. A motorboat propeller was used to generatebubbles with different concentrations at different times, up to the return to the natural subsurface layer. Theoretical consideration is given for these effects. The experimental data are in a reasonably good agreement with theoretical predictions.