CFD Simulation of Snow Fences

Session A1: Environmental Fluid Mechanics - Theoretical, Modelling and Experimental Approaches

Snow fences play a significant role in transporting snow away from roads, buildings and recreational areas. Although some guidelines for fence design exist these are mostly empirical in nature and are potentially difficult to apply in complex terrain and for multiple fences scenarios. Numerical modelling of the wind flow and snow transportation using Computational Fluid Dynamics (CFD) has the potential to allow site-specific topographies to be considered with multiple fence designs for optimisation. Manipulation of the snowfield to emulate climate change effects in New Zealand for a long term ecology monitoring project involved two angled porous fences set up with no knowledge of the interactions of the fences with each other or the topography. Due to site remoteness there is no opportunity to monitor the fence design effectiveness in the field. Numerous factors contribute to a successful fence design for this situation such as porosity, slat arrangement and angle to flow. Previous work studied varying fence porosity with a wind flow perpendicular to the fence. It was found that porosity is an important parameter of fence design and that slat arrangement may have some effect that needed to be quantified. This work extends the initial simulations and examines the effect the angle and orientation of the snow fence to the incoming wind has with different fence porosities and slat arrangements. The angling of snow fences is found to have the potential to allow manipulation of snow accumulation patterns although the relationship between fence design and positioning is complex. Numerical modelling has been shown to be effective as a tool for exploring fence design possibilities. It is recommended that simulations are undertaken in the design and planning stages for new fences to ascertain a more optimum combination of fence design and positioning for the prevalent wind direction.