Streaming generated by a bubble in an ultrasound field

A theory has been developed to calculate microstreaming velocity inside 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 harmonic vibrations). It has been demonstrated that the streaming velocity inside a bubble is much greater than that outside the bubble. It has also been shown that the microstreaming is most pronounced for a bubble undergoing volume resonance, which is in agreement with Elder’s experimental observations. If the viscosity of the gas medium in a bubble is neglected in theory, the results obtained agree qualitatively with Davidson and Riley’s.