A study of snow drifting on monoslope roofs during snowfall: Wind tunnel test and numerical simulation

The insight into the influences of roof slope on the characteristics of snow drifting on monoslope roofs during snowfall is still inadequate so far. Scaled tests of snow drifting on monoslope roofs with varying slopes (0 degrees to 25 degrees) were thus carried out in a wind tunnel equipped with a snowfall simulator, employing silica sand particles to model the snow precipitation environment. Typical snowdrift patterns on monoslope roofs were summarized, and elaborations were provided on the variation for the characteristics of snow drifting with roof slope. Similar features in terms of particle distributions, transport rate, and degree of erosion are observed for lower-sloped roofs (0 degrees, 5 degrees, and 10 degrees), which all differ from those on higher-sloped roofs (15 degrees, 20 degrees, and 25 degrees). The difference caused by the variation of approaching wind velocity on particle erosion is found to be more pronounced compared with that of snowfall intensity, and the increase in the degree of erosion with snowfall intensity can be reasonably represented by the linear relationship. The flow pattern around the roof and surface friction velocity before (without snow) and after snowfall (with snow cover) were then explored via numerical simulation for different roof slopes. Based on the simulated flow characteristics, the mechanisms of snow drifting on the sloped roofs under snowfall were further discussed.