Impact Dynamics of Natural Snowflakes on Engineered Surfaces

Blockage of air intake systems in vehicles due to snow accumulation in winter reduces engine power. To understand the risk better and mitigate it, computational fluid dynamics (CFD) models need to be developed for predicting the snow tracking property and the snow ingress amount into the air intake system. Such models require understanding of snow impact dynamics with various surfaces and determining so-called coefficient of restitution (COR). Here, a particle image velocimetry (PIV) method is used to obtain COR values of natural snowflakes impacting various engineered surfaces. Impact of surface properties (i.e., roughness and energy) and properties of snow (wetness, liquid water content, flake size) on the COR values are investigated. The results show that vertical COR substantially reduced as the impact angle increased. The horizontal COR dropped as impact velocity increased, but it was not significantly affected by impact angle. The findings of this study enable better prediction of snow accumulation and design of systems to minimize it, when needed.