CFD simulation of snow redistribution on gable roofs: Impact of roof slope

Abstract

A series of 2D steady RANS CFD simulations are conducted in this study to investigate the impact of roof slope on the snow redistribution on gable roofs. A small value of turbulent Schmidt number, which is calibrated by trapping efficiency from experiments, is adopted to enhance the snow particles’ turbulent diffusion in the CFD simulations for snow phase. And a scaled model test is conducted in the wind tunnel to validate the accuracy of numerical simulation, in which the silica sand was used to model snow particles. To uncover the mechanism of wind effects on the snow redistribution on gable roofs, the simulation results of wind-flow patterns, wall friction velocity of the roof surface, snow concentration and snow distributions are analyzed in detail for various roof slopes (5°–60°). Based on the features of wind-flow patterns and distribution patterns of snow, the gable roofs are classified into two categories: low slope where flow separates strongly at the leading edge and high slope where flow separates strongly at the roof ridge. The critical roof slope is between 20° and 25°.