Mechanisms of Colloid Detachment in a Sonic Field

Acoustic streaming for a particle oscillating parallel and perpendicular to a stationary wall has been investigated. The calculations carried out on particles with sizes between 0.01 micron and 10 micron. The drag and lift forces arising as a result of acoustic streaming are computed.

Velocity amplitude, frequency of oscillation, adhesion force and elastic properties of particle and surface to which the particle is attached are found to be the most important parameters controlling the detachment of particles. For small velocity amplitudes, the detachment mechanism is rolling whereas when velocity amplitudes are large, both rolling as well as lifting are important in the release process.