Radial and Translational Motion of Gas Bubbles in the Field of a Plane Piston and in a Progressive Flat Wave

Abstract

The radial and translational motion of small gas bubbles in the near field region of a pulsating piston and in a plane propagation sound wave was studied experimentally and by numerical simulations. It was established that the sub‐resonance size gas bubbles move toward the axis of symmetry of the piston‐zone of the pressure antinodes. As a result of convective diffusion and coagulation, those small bubbles, the nucleus of cavitation, grow in size. The special role of the rigid surface of the piston in keeping the bubbles near the surface is noted. It is established that while moving toward the node of pressure, the amplitude of the bubble pulsation increases, and nonlinearity results in typical cavitation noise on the sub‐harmonics of the main frequency. A series of cavitation impulses is noted. The fact that gas bubbles eject at a high speed from the zone of the antinodes of pressure away of the piston surface is established both by numerical simulations and experiments. Growth in size and the fact that the resonance radius depends on the amplitude both contribute to this ejection. Some generalization about the behavior of trans‐resonant bubbles in different inhomogeneous sound fields is made.