Development of a new k-ε model to reproduce the aerodynamic effects of snow particles on a flow field

This study aims to develop a new k-ε model that incorporates the effects of snow particles on a flow field. In the first part of this paper, the results of wind-tunnel measurements of a flow over a loose-snow surface are presented. The spatial distributions of the mass flux of drifting snow, wind velocity, and turbulence were simultaneously measured under several different wind-speed conditions. The wind-tunnel data clearly show that wind velocity near the snow surface decreased because of the snow particles. In the latter part of this paper, the basic equations of the k-ε model are modified to include new terms to express the effect of snow particles as moving obstacles on a flow field based on the concept of canopy-flow modeling. The model parameters included in the new terms, namely, R_p [which is a model parameter related to the moving particle speed in terms of the wind velocity (0<R_p<1)] and C_pε (which is a model coefficient included in the transport equation of energy dissipation rate), are optimized by comparing the wind-tunnel measurements and computational fluid dynamics predictions.