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This study aims to provide a multiphase approach that could better consider the snow drifting development on a building roof and then apply it to the investigation of the snowdrift development on a long-span spherical roof. Firstly, the CFD prediction accuracy for the flow field and the snowdrift on a two-level step building is examined by comparing simulated results with that of a field measurement. The windward snowdrift caused by building's blocking effect and trajectories of snow particles under the action of aerodynamic force and gravity are both well reproduced by incorporating an additional source term and a slip term into the transport equations. Secondly, the prediction accuracy of the snowdrift formed on a spherical roof is confirmed through the comparison with a wind tunnel test. The snow slipping effect at the edge of the roof is also well reproduced by considering the angle of repose of the snow. Based the validated approach, the snowdrift characteristics on a long-span spherical roof are investigated under different inflow velocity conditions. Three kinds of distribution patterns, i.e., the full-span balanced distribution, half-span unbalanced distribution and transitional distribution between them, are observed. Furthermore, the predicted results correspond well with the resultant design codes developed by ISO 4355. Finally, the size effect of the building roof on snowdrifts is explored by simulating the snowdrift on the spherical roofs with different spans. It is found that the spherical roof would have to bear a larger snow load with the increasing roof span, namely, the long-span spherical roof has more risks due to the adverse snow load. • The paper proposes a multiphase approach that could accurately predict the snowdrifts on long-span roofs. • The multiphase approach could well reproduce the motion of snow and the non-equilibrium drifting process. • Three typical snow distribution patterns on the spherical roof and their corresponding inflow velocities are specified. • The long-span spherical roof is more likely to experience the most adverse snow loads. [ABSTRACT FROM AUTHOR]

The meteorological conditions determine snow evolutions on and around buildings. Those climatic impacts have been independently considered in the current design codes of buildings, namely the wind pressure and the snow load. But snow load estimates are only based on precipitation assessments without considering the joint effect of wind and snow precipitation which lead to wind dominated deposition and snow transport. Thus, the statistics-based data provided by those building codes seem practically inadequate or at least incomplete. Using the data provided by upper-air and ground meteorological stations in northern China, including snowfall, wind velocity, and temperature, as indicators, we propose a series of statistical relationships covering aspects of snow precipitation and snow drifting. For those meteorological indicators that can affect building snow evolutions, more detailed analyses on their spatial and temporal changes have been achieved. The regionalization of snow precipitation features in northern China has also been proposed based on the clustering analysis on meteorological joint effects. The result shows that the snowfall in most northern regions of China is generally not heavy and in the form of a uniform deposition. The wind dominated depositions around buildings are more likely to appear in the regions around the Bohai Sea. • The simultaneousness of wind and precipitation in the snow load code is considered. • Climate impacts on snow evolutions on roofs are assessed via meteorological methods. • Regionalization of snow deposition features in northern China is acquired. [ABSTRACT FROM AUTHOR]

A modified Eulerian method for snowdrifts was proposed by introducing the snow particle capture efficiency. The relationships between the modified method and the previous methods were discussed, the results showed that the previous methods are special cases of the modified method. Based on the modified method, the impacts of the location and the height of the interfering building on the snow distribution on the target building were studied. The location of the interfering building seriously affects the snow distribution on the roof of the target building. Four typical interference modes were found through simulations. Significant interference effects on snow load occur when the interfering building is higher than the target building, and it becomes more powerful with the increase of the height of the interfering building. • A modified erosion and deposition model is proposed, introducing the capture efficiency of the falling snow phase. • The Impacts of the location of the interfering building on the snow distribution on the target building are investigated. • The Impacts of the height of the interfering building on the snow distribution on the target building are investigated. [ABSTRACT FROM AUTHOR]

This study conducted experiments on the wind-induced snow drifting around two adjacent cube models, using artificial snow in an open air snow-wind combined experimental facility constructed at the Harbin Institute of Technology (HIT). In particular, 20 experiments were conducted on two adjacent cubes with three different wind directions, three different wind speeds, and four different spacings. They were compared with contrast experiments with a single cube under the same inflow condition. The cube models were two wooden cubes having dimensions of 0.5 × 0.5 × 0.5 m. The drift process of natural snowfall was simulated by scattering snow particles. After snowfall for 25 min in each experiment, the snowdrifts were measured by surveying approximately 300 points around the cubes. Contour maps of the normalized snow depths were drawn and analyzed. The experiments show that the wind direction and speed have a certain influence on a snowdrift. Based on the wind-snow movement mechanism, the relationship between the snowdrift pattern around two cubes and the snowdrift pattern around a single cube was explored. Under the same condition, the snowdrift pattern around the multiple cubes can be deduced from the snowdrift pattern around the single cube. The snowdrift pattern around the downstream cube depends on its spatial position relative to the upstream cube. Moreover, the snowdrift between two adjacent cubes seems to be dependent on a funneling effect. • The process of wind-induced snow drifting was simulated by scattering artificial snow particles in an open air snow-wind combined experimental facility. • The influence of wind direction and wind speed on the snowdrift pattern around the cubes was studied. • Based on wind-snow movement mechanism, the relationship between snowdrift pattern around two cubes and snowdrift pattern around single cube was explored. Under the same conditions, the snowdrift pattern around the multiple cubes can be deduced from the snowdrift pattern around the single cube. • The effect of funneling has a profound effect on the snowdrift pattern between two adjacent cubes. • The snowdrift pattern around the downstream cube depends on its spatial position relative to the upstream cube. [ABSTRACT FROM AUTHOR]

To investigate the interference effects of building groups with flat roofs on snow load, a modified Eulerian-Eulerian model was proposed and verified by three typical cases. Based on the verified model, the impact of wind velocity on snow distribution on an isolated building with a flat roof was discussed first, and then a series of CFD simulations were carried out to investigate the snow distribution on building groups with the regular and staggered arrangement. The results showed that the amount of snow on the isolated building decreases significantly with the increase of wind velocity. The critical building density of the building group with the regular and staggered arrangement is about 0.25, above which the interference effects of the building groups on snow load are not significant. The interference effects of the building groups with the staggered arrangement on snow load are weaker than that of the building group with the regular arrangement. • A modified Eulerian model of snowdrift is proposed and verified. • The snow distribution on the isolated building is sensitive to wind velocity. • The interference effects on snow load are significant when building density is high. • The interference effects on snow load are seriously affected by building arrangement. [ABSTRACT FROM AUTHOR]