A ‘star drop’ refers to the patterns created when a drop, flattened by some force, is excited into shape mode oscillations
Abstract: “These patterns are perhaps best understood as the two-dimensional analogs 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.”
“Shape oscillation of a levitated drop in an acoustic field,” by W. Ran & S. Fredericks (Clemson University, Department of Mechanical Engineering)
