Impact cratering in sand: Comparing solid and liquid intruders

TL;DR

This study compares how solid and liquid intruders impact sand beds, revealing differences in crater size and depth, and identifying impactor-independent dissipation mechanisms in dense granular beds.

Contribution

It experimentally investigates the effects of intruder deformability on crater morphology, highlighting impactor-dependent and independent behaviors in granular impacts.

Findings

Crater diameter is larger for liquid droplets than for solid intruders.

Solid impacts produce deeper craters than liquid impacts.

Crater volume becomes independent of intruder deformability in dense beds with packing fractions over 0.58.

Abstract

How does the impact of a deformable droplet on a granular bed differ from that caused by a solid impactor of similar size and density? Here, we experimentally study this question and focus on the effect of intruder deformability on the crater shape. For comparable impact energies, we show that the crater diameter is larger for droplets than for solid intruders but that the impact of the latter results in deeper craters. Interestingly, for initially dense beds of packing fractions larger than 0.58, we find that the resultant excavated crater volume is independent of the intruder deformability, suggesting an impactor-independent dissipation mechanism within the sand for these dense beds.