Estimating the effect of pre-existing snowdrift on turbulent airflow and subsequent snowdrift in the numerical simulation

We investigated the effect of formed snowdrifts in advance on the turbulent flow and subsequent snowdrift distribution in a numerical simulation. We conducted an ideal numerical simulation for snowdrift distribution around three types of snow fences: two-dimensional fence, three-dimensional fence, and two-dimensional fence with a bottom gap. Snowdrifts resulting from an 8-hour drifting snow event were estimated by dynamically updating the bottom boundary conditions every 2 hours to reflect the developed snowdrift structures. Compared to simulation without boundary updates, snowdrift height on windward side of the two-dimensional fence was higher in the updated simulation. This increase was attributed to the weakened wind speed and modified snow particle trajectories around the previous snowdrifts. For the three-dimensional and bottom-gap fences, significant differences of snowdrift height were observed on the leeward areas between the updated and no-updated simulations. Snowdrifts on the leeward side of these fences were formed further downstream in the no-updated simulation. In contrast, the updated simulations generated snowdrifts closer to the fence on the leeward side. These findings suggested that neglecting the impact of the previous snowdrift structures in numerical simulation could lead to an overestimation of snowdrift development on the leeward side of obstacles.