Interaction force between a bubble and a solid particle in a sound field

The time-averaged interaction force exerted by a sound field between a gas bubble and a solid spherical particle is examined. An approach is developed allowing the force to be calculated for small separations between the bubble and the particle. The results obtained are compared with the existing asymptotic equation derived for large separations. It is shown that when the bubble and the particle are closely spaced, both the magnitude and the sign of the force are different from those predicted by the asymptotic equation, resulting in new interesting effects.