Downward jetting of a dynamic Leidenfrost drop

Abstract

Using ultrafast x-ray imaging, downward jetting of a Leidenfrost drop is observed and studied for the first time. The downward jetting is caused by capillary waves propagating on the bottom liquid-vapor interface during retraction of the drop. The downward jetting can be inhibited in the case of viscous damping of capillary waves. A jetting criterion depending on the Ohnesorge and Weber numbers is suggested: (Oh)(We${}^{2})\ensuremath{\le}66\ifmmode\pm\else\textpm\fi{}10$.

Topics & Concepts