The Nonlinear Scattering Characteristics of Sound Waves by a Bubble

Abstract

The scattering characteristics of sound waves by bubbles have been widely applied to ship tracking, wake-homing torpedo and reverberation suppression. To explore the nonlinear scattering characteristics of sound waves by bubbles, the Keller-Miksis equation of bubble vibration was adopted and a numerical solution to the nonlinear equation is presented. Then, the characteristics of nonlinear scattering, including the intensity of the scattered waves, the frequency and radius selection under pulse excitation and the scattered wave duration, are studied. The nonlinear scattered waves by a bubble are too small to be detected when the intensity of the excitation source is small. As the intensity of the excitation source increases, so does that of scattered harmonics by the bubble. If the intensity of the excitation source is further increased to a certain extent, the scattered waves by the bubble occurs dispersion phenomenon, emitting broadband noise. It may be the reason why a broadband noise will be produced by the cavitation of bubbles.