STATIC SHAPE OF AN ACOUSTICALLY LEVITATED DROP WITH WAVE-DROP INTERACTION

The static shape of a drop levitated and flattened by an acoustic stan ding wave field in air is calculated, requiring self-consistency betwe en the drop shape and the wave. The wave is calculated for a given sha pe using the boundary integral method. From the resulting radiation st ress on the drop surface, the shape is determined by solving the Young -Laplace equation, completing an iteration cycle. The iteration is con tinued until both the shape and the wave converge. Of particular inter est are the shapes of large drops that sustain equilibrium, beyond a c ertain degree of flattening, by becoming more flattened at a decreasin g sound pressure level. The predictions for flattening versus acoustic radiation stress, for drops of different sizes, compare favorably wit h experimental data.