Development of a large-eddy simulation coupled with Lagrangian snow transport model

Abstract

The aim of this study is to develop a large-eddy simulation (LES)-coupled Lagrangian snow transport model. This model consists of an LES for turbulent flow fields, and a particle transport simulation model based on Newton's equations of motion. Particles are treated as point masses for turbulent flow fields in this study. The interactions of momentum exchange between a fluid and particles are considered. The particle transport simulation includes three physical sub-processes on the snow surface: aerodynamic entrainment, rebound, and splash. Then, we simulated particle transport within a turbulent boundary layer under the low-wind condition in which saltation intermittently occurs. This simulation was calculated with high frequency and high resolution to capture the fine turbulent structures. The initial stage of saltation mainly related to sweeps, and particles were ejected through the process of aerodynamic entrainment. These ejected particle induced more saltating particles, and the number of saltating particles transported through the processes of splash and rebound increased and became dominant as time proceeds. In such processes of splash and rebound under low-wind conditions, the particle transport might be unaffected by turbulent structures.