In blessed memory of Professor Lev Grigoriyevich Kachurin, 
research advisor

ON THE THEORY OF FORMATION OF A SANDWICH
STRUCTURE OF A SPHERICAL HAILSTONE

R. G. Zakinyan

UDC 551.574+551.576

The paper analyzes the motion of the crystallization front 
under laminar and turbulent conditions of film motion on a hailstone 
surface. It is shown that the transition from one structure of ice 
to another is determined by both the equilibrium critical thickness 
of the film and the generalized Maclean parameter. A relation between 
them has been established. An expression for Kachurin's critical water 
content qK defining the dry-wet transition of the 
hailstone growth has been obtained. It is shown that the SchumannLudlam 
critical water content qSch-L gives only that value 
of the critical content at which droplets settled on the hailstone 
freeze. If qSch-L < q < qK, then a film 
is formed on the hailstone surface, but it is in an unstable state 
and, in the course of time, disappears, and the wet regime of the 
hailstone changes into the dry one. The hailstone will grow in the 
wet regime only at q > qK.

Mountain Geophysics Institute, Nal'chik, Russia; email: 
zakinyan@mail.ru. Translated from Inzhenerno-Fizicheskii Zhurnal, 
Vol. 76, No. 2, pp. 42-47, March-April, 2003. Original article 
submitted August 6, 2002; revision submitted September 30, 2002.