Additivity of the dynamic curvature of a thermocapillary depression and static curvature of a wetting meniscus

Abstract

A thermocapillary depression is induced by a laser beam in a layer of a transparent liquid on an absorbing substrate. Two plane-parallel wettable plates are immersed in the liquid in symmetrical positions with respect to the point of incidence of the beam on the liquid. The diameters of the thermocapillary response formed by the laser beam on a screen are studied in their dependence on the curvature of the equilibrium liquid meniscus formed between the plates. The property of additivity is experimentally proved; according to this property, the curvature of the free liquid surface is equal to the algebraic sum of the static curvature of the wetting meniscus and the dynamic curvature of the thermocapillary depression.