Impact of a Liquid Drop on a Granular Medium: inertia, viscosity and surface tension effects on the drop deformation

TL;DR

This experimental study investigates how liquid drop impacts on granular media are influenced by inertia, viscosity, and surface tension, revealing new scaling laws for crater size and drop extension.

Contribution

The paper introduces new empirical scaling laws for crater diameter and drop extension based on impact energy and Weber number, differing from previous literature.

Findings

Crater morphology depends on impact energy and fluid properties.

Drop maximal extension scales as We^{1/5}.

Crater diameter scales as E_K^{1/5}.

Abstract

An experimental study of liquid drop impacts on a granular medium is proposed. Four fluids were used to vary physical properties: pure distilled water, water with glycerol at 2 concentrations 1:1 and 1:2 v/v and water with Tween 20 at the concentration of 0.1g/l. The drop free fall height was varied to obtain a Weber number (We) between 10 and 2000. Results showed that obtained crater morphologies highly depend on the impacting drop kinetic energy E_{K}. Different behaviours during the drop spreading, receding and absorption are highlighted as function of the fluids viscosity and surface tension. Experimental absorption times are also commented and compared with a simplified theoretical model. Drops maximal extensions and craters diameters were found to scale as $We^{1/5}$ and $E_K^{1/5}$ respectively. In both cases, found dependencies are smaller than those reported in literature: $We^{1/4}$ for drop impacts on solid or granular surfaces and $E_K^{1/4}$ for spherical solid impacts on granular media.