## 3 Results and Discussion  
Typical photos of the tests are shown in Figure 4. The working conditions are represented by the case number, such as \"\(D/H0\)\"-\"\(H/H0\)\"-\"\(WD\) (Wind Direction)\". Here, the case number of \"isolated\" represents the wind tunnel test of the target building without an interfering building. Due to the limitation of the measuring equipment, only the snow depth of the central line along the wind direction on the target building was measured and normalized by the initial snow depth, and the results are shown in Figures 5-7. The \(h0\) and \(h\) are the snow depths on the low-rise building roof before and after wind tunnel tests, respectively; \"\(x\)\" is the distance between the measured points and the windward eave. According to Figure 4, the snow layer on the roof of the target building is two-dimensional for cases of wind directions of 0 and 180 degrees for the interfering building positioned upstream and downstream of the target building. In these conditions, the snow depth of the central line can represent the whole snow distribution on the target building. However, the snow layer on the target building for the 90-degree cases is highly three-dimensional for the buildings placed side by side. To describe the snow distribution of all conditions, the mass of particles blown off from the target building was also recorded and normalized by \(m0\), which is the recorded mass of particles blown off from the target building under the isolated working condition, as shown in Figures 4-7. The snow depth of the central line combined with the mass of particles blown off from the target building and the photos of the experiments can reflect the overall situation of the experiments. Figure 5 shows the results of cases for the wind direction of \(0^{\circ}\), and the interfering building positioned upstream of the target building. The wind velocity of the target building at the eave height is decreased, and the snow in the front of the target building roof (\(x/L<0.4\)) is significantly accumulated when compared with the case isolated due to the shelter effect of the interfering building. According to Figure 5, when \(H/H0=1\), the wake flow of the interfering building leads to an increase of the friction velocity on the roof of the target building, where \(x/L>0.4\), resulting in a lower snow depth than that of the isolated condition. When \(H/H0>1\), the snow depth on the target building is larger than that of the case isolated due to the shelter effect of the interfering building. The peak values of the normalized snow depth on the target building are larger than that of the isolated case. With the increase of the height of the interfering building (\(H\)), the snow distribution tends to be uniform, and more areas on the target roof are affected by the interfering building, and the shelter effect becomes powerful. With the increase of the \begin{table}
\begin{tabular}{c c c} \hline \hline
**Description** & **Prototype** & **Wind Tunnel Test** \\ \hline \hline Eave height of the target building (m) & 4 & 0.08 \\ Wind velocity at eave height (m/s) & 5.4 & 7 \\ Initial snow depth (cm) & 45 & 0.9 \\ Time duration (min) & 29.1 & 5 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Parameters of the wind tunnel tests and prototypes. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Similarity Parameters** & **Prototype** & **Wind Tunnel Test** \\ \hline \(\frac{h_{0}^{2}}{2g^{2}}>30\) & & 61.8 \\ \(\frac{\rho}{\rho_{n}-\rho_{n}^{2}}\) & 0.134 & 0.015 \\ \(\frac{U(H)}{H_{i}}\) & 27 & 27 \\ \(\rho_{s}/\rho>600\) & & 2272.7 \\ \(\frac{\rho_{s}}{\rho_{n}-\rho_{n}^{2}}\frac{U(H)^{2}}{g^{2}H}\) & 0.8 & 62.5 \\ \(\frac{\rho}{H_{i}}\) & 0.037–0.185 & 0.086 \\ \(\frac{\rho}{\rho_{n}}\  
As shown in Figure 5d, the mass of particles blown off from the target building is close to \(m0\) when \(H/H0=1\) and more particles are blown off the target building roof when compared with the isolated condition with the increase of the height of the interfering building and the decrease of the building spacing.