Video from the paper "Shape oscillation of a levitated drop in an acoustic ﬁeld," by W. Ran & S. Fredericks (Clemson University, Department of Mechanical Engineering), http://arxiv.org/abs/1310.2967
Abstract: "A 'star drop' refers to the patterns created when a drop, ﬂattened by some force, is excited into shape mode oscillations. These patterns are perhaps best understood as the two dimensional analog to the more common three dimensional shape mode oscillations. In this ﬂuid dynamics video an ultrasonic standing wave was used to levitate a liquid drop. The drop was then ﬂattened into a disk by increasing the ﬁeld strength. This ﬂattened drop was then excited to create star drop patterns by exciting the drop at its resonance frequency. Diﬀerent oscillatory modes were induced by y varying the drop radius, ﬂuid properties, and frequency at which the ﬁeld strength was modulated."