The reflection of drops off hot surfaces

Kurzfassung

When a drop approaches a hot surface the vapor production can be so high that the drop is reflected without wetting the surface. This phenomenon that occurs when the temperature of the surface is above a critical value, is modeled by approximating the drop by a rigid liquid disk. The flow of the vapor in the gap underneath the disk is considered to be inviscid and incompressible. Thus the inertia of both the drop and the vapor are of primary importance. The disk model describes the main features of the drop-surface interaction. In particular, the kinetic energy of the reflected drop is reduced. This is also observed in experiments but has previously been attributed to viscous dissipation only.