Impact of a Single Drop on a Liquid Film: Experimental Analysis and Comparison with Empirical Models

Photographic techniques were used to study the impact of single water drops impinging on a liquid film. The fluid motion was studied by means of a CCD camera (1?s exposure time), and the use of a transparent glass wall allowed observing the impact phenomenon from below the wall by a proper optical set-up. The crown evolution was quantitatively studied through the measurement of various parameters like: crown diameter (internal and external), crown elevation, number of jets protruding from the upper rim as well as their average size and growth rate. The gathered quantitative data allowed a thorough analysis of the process, and some interesting features of crown evolution are reported together with comparison with existing models.