THE VISCOUS ACOUSTIC FIELD IN LIQUID-DROP POSITIONING FORCING IN AN ACOUSTIC LEVITATION CHAMBER

The development of acoustic levitation systems has provided a technolo gy with which to undertake fundamental studies of free drop dynamics a s well as processing experiments. Acoustic levitation chambers utilize radiation forces to position the drop. Moreover, drop oscillations ca n be induced via frequency modulation of the acoustic wave. The modula ted acoustic radiation vector, itself a projection of the radiation st ress, acts as the driving force for the drop oscillations. If the acou stic field is considered to be inviscid, only the radial component of the radiation force exists. In order to account for the tangential for cing, it is necessary that the effects of viscosity be included in the acoustic field. This work determines the viscous acoustic field. The effects of viscosity contribute in a thin layer near the drop/host flu id interface. The method of composite expansions is employed in the de termination of the acoustic field with viscous effects taken into acco unt.