Frozen impacted drop: From fragmentation to hierarchical crack patterns

TL;DR

This study explores how water drops freezing on cold surfaces create different crack patterns, transitioning from simple fragmentation to complex hierarchical fractures as temperature and impact conditions vary.

Contribution

It experimentally demonstrates the transition from 2D fragmentation to hierarchical crack patterns in frozen water drops based on substrate temperature and impact parameters.

Findings

Crack patterns depend on substrate temperature and impact conditions.

Transition from fragmentation to hierarchical cracks occurs below a critical temperature.

Phase diagram maps regimes based on impact parameters.

Abstract

We investigate experimentally the quenching of a liquid pancake, obtained through the impact of a water drop on a cold solid substrate ($0$ to $-60^\circ$C). We show that, below a certain substrate temperature, fractures appear on the frozen pancake and the crack patterns change from a 2D fragmentation regime to a hierarchical fracture regime as the thermal shock is stronger. The different regimes are discussed and the transition temperatures are estimated through classical fracture scaling arguments. Finally, a phase diagram presents how these regimes can be controlled by the drop impact parameters.