STREAMING GENERATED BY A BUBBLE IN AN ULTRASOUND FIELD

A theory has been developed to calculate microstreaming velocity insid e and outside an isolated air bubble in a liquid produced by a bubble- scattered sound field, taking account of two predominant modes of the bubble's motion: a monopole (pulsation), and a dipole (translational h armonic vibrations). It has been demonstrated that the streaming veloc ity inside a bubble is much greater than that outside the bubble. It h as also been shown that the microstreaming is most pronounced for a bu bble undergoing volume resonance, which is in agreement with Elder's e xperimental observations. If the viscosity of the gas medium in a bubb le is neglected in theory, the results obtained agree qualitatively wi th Davidson and Riley's. (C) 1997 Acoustical Society of America.