Yuren Tian
Robert E. Apfel
Ctr. for Ultrasonics and Sonics, Yale Univ., New Haven, CT 06520-8286
Many different kinds of levitators are used to study liquid drops. In most of them, only a single drop can be levitated. Under some circumstances, however, it is desired to levitate multiple drops simultaneously. An acoustical levitator has been modified for the purpose of multiple-droplet levitation. During the experiments, a liquid is poured on the surface of the acoustic transducer and is ultrasonically atomized. By applying a static electric field on the surface of the liquid, the atomized drops are electrically charged. After the drops are dispersed into the levitator, they can be contained together and levitated by acoustic radiation force. Coalescence among the drops is prevented by the forces of electric repulsion. The separation distance between the drops, the droplet size, and the number of levitated drops can be controlled by the intensity of the acoustic and electric fields. Preliminary experimental results will be reported, including the observation of mass transfer among the levitated drops. [Work supported by NASA through JPL, contract 958722.]