Theoretical and experimental study on mechanical characterisation of a water drop impact on a solid surface

Abstract

The drop impact phenomenon can be used to study many agricultural aspects related to the rainfall, runoff and irrigation, such as the stability of aggregated and the detachment of fine particles. The aim of this study was to study experimentally and numerically the water drop impact on a solid wall. In a first phase a simple experimental apparatus and basic theoretical concepts were used to investigate the influence of the drop speed on the impact pressure. In the second section, a finite element model able to reproduce the complex phenomenon observed in the experimental phase, was developed. The pressure values obtained by experimental measurement are similar to those calculated on the base of the energy conservation principle (average percentage difference of 15.6%). Numerical model was useful to obtain important information on pressure profile inside the drop and the impact pressure during the splash, at present hard to achieve experimentally. The model was used to estimate also an almost realistic dynamic behaviour of the spreading drop.