CFD Simulation of Snow Distribution on an Isolated Flat Roof with Different Perimeter Walls

This study addresses the gap in understanding snow distribution on flat roofs lacking a four-sided perimeter wall. A computational fluid dynamics (CFD) model, validated by wind tunnel tests, was employed to investigate how the integrity of perimeter walls affects snow load formation. The findings reveal that the windward perimeter wall plays a crucial role in creating high snow loads, which leads to the formation of a distinct core zone at the center of the roof due to vortex convergence. Snow loads decrease as the number of open perimeter walls increases, with the most significant reductions observed in roofs with two open sides, specifically when both the windward and sidewall openings are present. In this configuration, aerodynamic effects limit vortex development. Meanwhile, the leeward and sidewall perimeter walls mainly serve to redistribute snow, having minimal impact on the overall magnitude of the load. This study reveals the physical mechanisms governing snow distribution by examining how perimeter walls alter flow fields and modulate snow particle transport pathways, leading to engineering recommendations for snow load design on flat roofs.