Freezing a rivulet

TL;DR

This study experimentally examines the formation and growth dynamics of a stable ice structure created by a thin water rivulet on a cold surface, revealing two distinct growth regimes influenced by heat flux and boundary layer confinement.

Contribution

It provides a quantitative analysis of the formation process and identifies two growth regimes, enhancing understanding of ice formation in capillary water flows.

Findings

Identification of a 1D diffusive solidification regime.

Discovery of a linear thickening regime influenced by heat flux.

Explanation of the linear growth through thermal boundary layer confinement.

Abstract

We investigate experimentally the formation of the particular ice structure obtained when a capillary trickle of water flows on a cold substrate. We show that after a few minutes the water ends up flowing on a tiny ice wall whose shape is permanent. We characterize and understand quantitatively the formation dynamics and the final thickness of this ice structure. In particular, we identify two growth regimes. First, a 1D solidification diffusive regime, where ice is building independently of the flowing water. And second, once the ice is thick enough, the heat flux in the water comes into play, breaking the 1D symmetry of the problem, and the ice ends up thickening linearly downward. This linear pattern is explained by considering the confinement of the thermal boundary layer in the water by the free surface.