## Verification of the New Approach
### Experiments for the Verification of Reliability
#### 3.4.3 Results and Discussion  
There are two key factors to evaluate the accuracy of snowdrift given by the experiments. One is the similarity of the shape of snowdrift; another is the similarity of the snow distribution coefficient. The distribution coefficient is the ratio of measured snow depth and average snowfall at any measuring point. Figure 12 shows the contour maps of the snowdrift geometry around the model of field observation and scale experiments. The photos of scale experiments are shown in Figure 13. All of the contour maps showed a similar shape which was formed like a horseshoe, in which snow mainly accumulated at the front of the windward side and beginning at the two corners of the windward side, there were two distinct erosion areas near the lateral sides along the downwind direction. From the comparison, if just focusing on the overall distribution shape of the snowdrift, it seemed that the result when the scale was 1/10 was more similar to the field observation and the main erosion areas (near the lateral sides) were larger than field observations for the other scale experiments. The basis for explaining this phenomenon needs an objective and appropriate understanding of the result of the field observation. The main erosion is more distinct in the experiment due to the stable wind speed. However, sometimes there were slight or no wind during the field observation, and snowfall contributes more to decrease the erosion effect in this condition, which would decrease the non-uniform snow distribution to some extent. However, considering that two distinct snowdrifts were formed in front of the windward side, the results of the 1/1, 1/2, and 1/4 scale experiments had a more similar characteristic of snow distribution. When the scale was 1/10, the snow only accumulated at the feet of the windward side, indicating that wind velocity was excessively reduced; the near to the ground reverse flow in front of the windward side was weak and could not transport snow particles away from the windward side, so that only one distinct snowdrift was formed. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Similarity Parameters** & **Prototype** & **1** & **0.5** & **0.25** & **0.1** \\ \hline \(D_{p}/L\) & 0.002 & 0.003 & 0.006 & 0.012 & 0.03 \\ \(\frac{\rho}{\rho-p}\frac{u_{0}^{2}}{\delta D_{p}^{2}}\) & 0.0116 & 0.01  
Figure 12: Contour maps of the snowdrift geometry around the model: (**a**) field observation; (**b**) experiment with a 1 m Cube model; (**c**) experiment with a 0.5 m Cube model; (**d**) experiment with a 0.25 m Cube model; and (**e**) experiment with a 0.1 m Cube model. Considering that the effect of fluctuant wind velocity in the field observation could not be ignored, the 1/1 model may be treated as the self-test prototype. In this situation, according to the comparison of results, the 1/2 and 1/4 scale experiment results would have relatively acceptable accuracy of the reproduction of the snowdrift shape of the field observation, but the 1/10 scale experiment result would have a lower precision reproduction. In order to compare the snow distribution in a more precise method, Figure 14 compares the snow distributions along lateral and streamwise lines crossing the model. In Figure 14a, it could be seen that the snow distribution of the field observation has obvious characteristics: Near the windward side, the snow formed a compressed \"N\" shape, and near the leeward side, there formed a compressed \"U\" shape. When the scale was 1/1 and 1/2, the distribution  
Figure 14: Comparison between normalized snow depths obtained from field observations and scale experiments: (**a**) streamwise direction (center section) and (**b**) lateral direction (center section). Figure 13: Photos of scale experiments. results showed a good agreement with the field observation, even though the position where the extreme value occurred moved towards to the windward side as the scale ratio decreased.