Abstract
A numerical model of powder snow avalanches is developed based the tllermal model in the field of fluid mechanics. The model consists of theconservative equation of fluid phase, the conservative equation of the solid phase, the momentum equation and the equation of the kinetic energy of turbulence. Some constitution relationships, i. e. the entrainment coefficients of ambient fluid, the entrainment coefficient of snow particles on the bed and the shape facotors are expressed by the functions of the slope angle. This model is examined by the experimental data of inclined thermals using the mixture of water and solid particles in the laboratory. The numerical calculations are carried out to simulate the powder snow avalanche occurring at the Yokokura, Katsuyama city in Fukui Prefecture. The reasonable numerical results are obtained. It can explain the longitudinal variations of the height, the speed, the concentration of snow particles, the kinetic energy of turbulence and the distructive power of the avalanche.
