The influence of an acoustic field on the dispersed phase of a fluid has been studied in connection with the application of acoustic coagulation for the precipitation of gases. An acoustic field, depending on the intensity and frequency of the wave, as well as the physical condition of the medium, may cause coagulation, i.e. the joining of small particles into larger aggregates. This paper gives an example of the applications of dispersed phase acoustics, with particular emphasis on recent developments, e.g. the acoustic method of airport fog precipitation. This innovative technology is based on the fact that water can be collected from fog under the influence of acoustic waves. This work presents the new results of the analysis of the action of the acoustic field on the fog.

This work deals with the problem of ultrasound in the context of biomedical and clinical applications. Ultrasonic waves can be used for the separation of cells in human blood. Under the inuence of ultrasonic waves cells included in the liquid experience a certain characteristic displacement was referred to as drift. Presented work suggests that only radiation pressure should be taken into account as a mechanism of drifting in this situation. It has been demonstrated that the growth of cells concentration around the points of stable equilibrium is exponential. The time constant of this growth was estimated and the formulae which determine the time needed to obtain the assumed concentration increase have been derived. The theoretical studies of acoustic agglomeration of particles in the liquid have become a new focus in the ultrasonic research.

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This work deals with the problem of ultrasound in the context of biomedical and clinical applications. Ultrasonic waves can be used for the separation of cells in human blood. Under the inuence of ultrasonic waves cells included in the liquid experience a certain characteristic displacement was referred to as drift. Presented work suggests that only radiation pressure should be taken into account as a mechanism of drifting in this situation. It has been demonstrated that the growth of cells concentration around the points of stable equilibrium is exponential. The time constant of this growth was estimated and the formulae which determine the time needed to obtain the assumed concentration increase have been derived. The theoretical studies of acoustic agglomeration of particles in the liquid have become a new focus in the ultrasonic research.

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.