## 1 Introduction  
Since ancient times, buildings have been constructed to protect people from the natural environment. The environment dictates what type of building should be constructed, and snow loads are one of the dominant live loads that should be considered in the design of buildings in cold regions with a severe winter climate. Investigations show that snow loads are usually unbalanced, due to the action of the wind. And snowdrifts around buildings may cause problems for the vehicular traffic and pedestrians. Currently, field observations, numerical simulations, and wind tunnel tests are the three main methods to estimate snow distribution, and much work has been undertaken to explore how the wind affects snow distribution. Field observation is the most direct and reliable approach for obtaining information on snow distributions. Investigations of snowdrifts around an isolated building or group of buildings have been carried out in several previous studies [1; 2]. [PERSON] and [PERSON] [3] investigated the snowdrifts around three different model buildings in a valley in Spitsbergen, Norway, and the results showed that a change of roof shape could lead to large differences in snow distribution around the building, [PERSON] et al. [4] carried out research to investigate the snowdrift around a \(2.0\times 2.0\times 2.0\) m\({}^{3}\) cube at the SANAE IV research station, Antarctica, during the summer of January 2002 and verified the accuracy of a numerical simulation model using the results of field observations. [PERSON] [5; 6] measured snow loads on nearly 200 building roofs under different wind and sun/shade environments from 1966 to 1986 in southern Norway. This method has strict requirements on the environment of the test site, such as wind velocity, temperature, humidity, and snowfall, but these important parameters in the observation were unstable and uncontrollable. In 1991, [PERSON] [7] first used numerical simulation to analyze snowdrifts, and now this method is widely used by researchers. [PERSON] et al. [8] analyzed the snowdrift around an actual apartment building using the revised k-\(\varepsilon\) model. [PERSON] et al. [4] predicted transient snowdrift around a cubic structure using the standard k-\(\varepsilon\) model. And a large amount of numerical work has been done recently due to its significant advantage in efficiency and convenience [9; 10; 11; 12]. However, only a few attempts have been made to apply CFD (Computational Fluid Dynamics) to roof loading so far [13]. [PERSON] et al. [14; 15] predicted the snow distribution on a curved roof of a sports hall located in Oslo and compared the results with measurements. Some researchers are confused by the selection of the turbulence models, hence there is no approved and unified model. Wind tunnel testing [16; 17; 18] is the most effective method for investigating snow distribution under the action of airflow. [PERSON] [19; 20] identified the important similarity criteria by analyzing the saltation process and discussed the necessary compromises in the modeling procedures. [PERSON] et al. [21] used artificial snow to simulate snow drifting around buildings for the Antarctic Concordia research station. [PERSON] et al. [22] investigated the development of drifting snow in a boundary layer wind tunnel. [PERSON] et al. [23] conducted a series of experiments in a wind tunnel to investigate the motion of natural snow and found that the threshold wind speeds for fresh and old snow were 6.2 m/s and 6.8 m/s (at 10 m height). [PERSON] et al. [24; 25] investigated the snow distribution on a stepped flat roof using different granular materials in an open straight-circuit wind tunnel and also conducted a series of experiments on snow loads on flat roofs using high-density silica in the open test section of a boundary-layer wind tunnel. However, the snowdrift simulations in a boundary-layer wind tunnel struggle with scaling issues and similarity criteria.