Influence of acoustical field on small particles

Abstract
The paper concerns the problem of the drift of small particles suspended in acoustic field. It is shown that the drift occurs in acoustic fields in which the amplitude of medium velocity depends on the position of the particle. In contrast with other mechanisms used to explain the drift of small particles, the effect can be derived even in acoustic field of infinitely small amplitude. This type of drift, called the asymmetry drift, is discussed for the plane progressive wave, for the plane standing wave, and for the spherical progressive wave. Some remarks are made on the two-dimensional standing wave problem.