Field measurements and numerical simulations of snow transport and deposition around structures and into ventilation intakes

This work is concerned with field experiments and measurements, and numerical simulations of aeolian snow transport, especially the snow deposition on structures and around obstacles. The research work is interested in measuring snow deposition on a few existing structures and comparison with two international snow load standards. Furthermore, the work is interested in either physical or numerical modeling of the atmospheric boundary layer wind flow and its associated blowing snow processes by means of outdoor experiments (scaled or full-scale) and Computational Fluid Dynamics (CFD), respectively. Several experiments and measurements are carried out to capture characteristic behavior of snow deposition on existing roofs and around obstructions. The obtained data is presented and compared with international standards. Also, an example of obstruction of T and I' shape, which is not introduced in standards is shown. The characteristic behavior is observed and compared to similar but reported obstructions. The numerical modeling firstly focuses on the turbulent transport of airborne snow particles. The model is validated using experimental data on snow infiltration into an opening. The model is subsequently applied in an engineering application to determine the snow infiltration into ventilation intakes of various design in terms of relative snow removal efficiency and daily amount of infiltrated snow. The other focus of the numerical simulation relates the snow transport and the change in snow surface. The deposition model was applied to a case of solid snow fence and a building with a curved roof. Since experimental data has been obtained for both applications, necessary characteristic properties and functions in terms of means are determined and used to set boundary conditions of the model. That is wind profile, horizontal snow mass flux profile and the value of threshold wind friction velocity. Similarly, the boundary conditions are determined for all conducted study cases of snow fences. Furthermore, a gabled roof of various dimensions is studied based on field observations, showing that the snowdrift on the roof starts developing at the ridge and continues downwind. This study shows interconnection between application of snow load standards, field experiments and numerical simulations to achieve characteristic distribution of snow cover on structures. It is shown that though limited, all modeling methods can collaborate in cases some method shows difficulties. An alternative method to determine the drift snow load is introduced. It is based on meteorological data and trapping efficiency which can be obtained from wind tunnel. It relates the horizontal snow transport, trapping efficiency and the effect of exposure. The conducted field experiments and measurements on existing structures provide valuable data which are necessary for validation of models. Also, the procedure to determine characteristic properties in terms of mean values is presented. Furthermore, it is shown how snow infiltration into Heating Ventilation and Air conditioning (HVAC) intakes can be estimated by using CFD. The numerical simulations of snow deposition on structures, though sometimes provide good results, show space for improvement, mainly to achieve correct time scaling. Nevertheless, the numerical simulations show the ability to predict the shape of the snowdrift, which might in combination with standards can estimate snow load distribution of special cases of constructions