1998 年 114 巻 11 号 p. 776-782
The particles in water form regular stripes of clusters when a standing wave is generated in a tube. With increasing particle concentration, the particles are moved up to the upper part of the tube by lift force and make massive clusters. The lift force is resulted from the dissipation of the wave. The first purpose of this paper is to measure the total dissipation of low frequency ultrasonic wave transmitted in water containing polystyrene beads. The dissipation rate is approximately proportional to the volumetric concentration of the particles. The second purpose is to simulate the cluster formation with the method superposing Oseen's flow flied of each sphere moving at low Reynolds number. The simulations of five and three settling particles resemble the relative position of particles observed in the experiments. Simulations of the cluster result in similar formation of clusters obtained in the experiments. However, the velocity of a particle cloud moving in the same direction is overestimated by this method.