Deformation of a Liquid Drop Fallen on the Stationary Oil Surface. Influence of Surface Tension and Kinematic Viscosity of the Drop.

Deformation of a liquid drop fallen on the stationary silicone-oil surface was examined in detail. Special attention was directed to the influence of the liquid-drop and silicone-oil properties on the deformation of the drop after the impact with the oil surface. Water solutions of ethanol or glycerin with various concentrations were used for liquid drop to control its surface tension σL and kinematic viscosity νL. Various kinds of silicone oils were tested that cover a wide range of kinematic viscosity νT, 1∿(10)5(mm)2/s, under nearly a constant surface tension. The drop diameter at its maximum spread, dM. is influenced by not only σL and νL of the drop itself but also νT of the silicone oil. The influence of σL on dM is pronounced under the condition of νT<(10)2(mm)2/s, whereas νL has a significant influence on dM over the whole range of νT. With highly viscous silicone oil of νT>(10)4(mm)2/s, dM/dL (dL : initial diameter of drop) for all σL and νL can be well correlated by Reynolds number and Ohnesorge number.