Marangoni instability of two liquids mixing at a free surface

Abstract

The impact of a water drop on a thin layer of glycerin leads to the formation of an intricate flower-like pattern. We show that these leaf-like forms are generated by a surface-tension instability at the air-liquid interface along which there exists variable concentration of glycerin and water. Spatial variations of surface tension drive intense vortices inside the water layer, which interact with the glycerin-water concentration at the surface. Horizontal bending of these vortices is reinforced by the resulting enhancement of the surface-tension gradients. © 1998 American Institute of Physics.