ИСТИНА

The movement of a small stiff spherical particle in the standing wave pressure field in fluid is studied taking into consideration the Basset force. The integro-differential equation is solved using the Krylov-Bogolyubov averaging technique and the efficient numerical scheme for the solution of the obtained averaged integro-differential equation is proposed. The transition from "fast" variables to "slow" averaged coordinates provided the averaged particle trajectory and its qualitative behavior. It is shown that the Basset force may play serious role in focusing small particles by ultrasound and even may change their focusing position from standing wave nodes to antinodes. The obtained results are investigated analytically and numerically.