Interaction of Cavitation Bubbles in Acetone at Their Strong Enlargement and Collapse

Abstract

The influence of the hydrodynamic interaction of cavitation bubbles in acetone on the deformation of their surfaces during their single joint strong expansion and collapse is investigated. The bubbles are initially spherical and are located at the pressure antinode of an ultrasonic standing wave. Two configurations of the relative position of the bubbles are considered. The first configuration (linear) consists of three equally-spaced bubbles. Their centers are located in one straight line. The second configuration (planar) consists of nine bubbles. Their centers are located at the nodes of a uniform square grid located in one plane. The main attention is payed to the dynamics of the central bubbles. It is found that in both configurations, the deformations of the central bubbles in the form of the second spherical harmonic are significantly greater than in the form of other harmonics with higher numbers. In the final high-speed stage of collapse, the interaction between the bubbles becomes insignificant. At the end of collapse, the central bubble in the linear configuration appears flattened along the axis of symmetry, whereas in the planar configuration, it is elongated along the normal to the plane of the bubble centers.