ON THE MUTUAL INTERACTION OF 2 GAS-BUBBLES IN A SOUND FIELD

The expression for the mutual interaction force between two pulsating gas bubbles immersed in an incompressible and inviscid fluid is derive d assuming that the distance between the bubbles is comparable to thei r sizes. The results of numerical calculations for air bubbles in wate r are presented. They show that at small distances between the bubbles the interaction force is substantially different from that given by B jerknes' theory [Fields of Force (Columbia University Press, New York, 1906)] in which the separation distance between the bubbles is assume d to be large in comparison with the bubble sizes. The discrepancy see ms to result from the effect of multiple scattering which is no longer negligible when the bubbles come close to each other. The present stu dy enables one to understand the mechanism of the formation of the sta ble bubble clusters (''bubble grapes'') observed experimentally by Kob elev et al. [Pis'ma Zh. Eksp. Teor. Fiz. 30, 423 (1979)]. (C) 1995 Ame rican Institute of Physics.