Aerodynamical Effects in Snow Crystal Growth

TL;DR

This paper reviews how aerodynamical forces influence snow crystal growth, morphology, and symmetry, highlighting their role in forming unique structures like triangular snow crystals through flow and orientation effects.

Contribution

It provides quantitative estimates of aerodynamical forces and explores their impact on snow crystal growth and morphology, especially the formation of triangular crystals.

Findings

Aerodynamical forces can stabilize or destabilize snow crystal growth.

Air flow affects growth rates via ventilation effects.

Aerodynamics likely cause triangular snow crystal formation.

Abstract

We review several aspects of aerodynamics that affect the growth, morphology, and symmetry of snow crystals. We derive quantitative estimates for aerodynamical forces that orient falling snow crystals, estimate how air flow around snow crystals affects their growth rates (the ventilation effect), and examine how the combination of orientation and growth modification can stabilize or destabilize different growth behaviors. Special attention is given to the formation of triangular snow crystals, since it appears that aerodynamical effects are responsible for producing this unusual morphology, both in nature and in the laboratory.