Architecture of open source program for numerical modeling of flows on mountain slopes

In this paper, we compare two approaches to describe the dynamics of flows on mountain slopes using the depth-averaged equations of continuum mechanics and using the complete, not depth-averaged, equations of continuum mechanics for three-dimensional modeling. Using these two approaches, a simulation of an experimental slush flow in the tank and the interaction of the flow with dam barrier protection was carried out. Numerical solutions are compared with experimental data. Also, both approaches are applied to the calculation of an avalanche in the 22nd avalanche cite of Mount Yukspor (Khibiny). Avalanche run-out distance and the shape of the avalanche deposits are compared with field data obtained from the measurement of a real avalanche. In the course of a numerical experiment, distributions of such quantities as flow velocity, depth, density, molecular and turbulent viscosity, values of the density of turbulent kinetic energy, dissipation of turbulent kinetic energy, and shear stress at the bottom of the flow were obtained. Using the obtained data a mathematical model is developed to describe the entrainment of the underlying material by the flow during slope erosion and the deposition of the flow material on the slope. To implement the obtained mathematical model, the architecture of the multiphaseEulerChangeFoam solver was developed, which implements a three-phase multi-velocity model with phase exchange between the material of the underlying surface and the material of the flow. The classic solver multiphaseEulerFoam from the OpenFOAM package is taken as a basis for the developed solver.