## 3 Simulation Results and Analysis
### External Simulation Results for Summer  
The Evaluation Standard for Green Building in China (GB/T50378-2019) [37] specifies that the evaluation criteria for the outdoor wind environment in summer involve the size of the vortex area and the windless zone, along with the wind pressure difference between the interior and exterior surfaces of the building's external windows. Figure 9 shows wind speed vector diagrams at a height of 1.5 m above the ground for four scenarios, with vortex locations indicated by red dots. Scenario 1 is the only one that does not display vortex areas, while the other three do. Scenario 1's row-by-row floor planning does not create a solid blocking surface, which enables the wind to move freely over the entire site, preventing the development of vortex zones. However, other scenarios create enclosed and semi-enclosed regions that obstruct airflow. In Scenario 4, the enclosed courtyard creates a restricted space, leading to stagnant airflow within the courtyard and the formation of a larger vortex area. In Scenarios 2 and 3, the vortex zones are mostly focused on the leeward side, known as the low-pressure vortex region.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{3}{*}{**Scenarios**} & \multirow{3}{*}{\begin{tabular}{c} **Average Windward** \\ **Window Pressure** \\ **(Pa)** \\ \end{tabular} } & \multirow{3}{*}{\
\begin{tabular}{c} **Average Leeward** \\ **Window Pressure** \\ **(Pa)** \\ \end{tabular} } & \multirow{3}{*}{
\begin{tabular}{c} **The Difference in** \\ **Average Wind** \\ **Pressure between** \\ **the Windward and** \\ **Leeward Sides of the** \\ **Window (Pa)** \\ \end{tabular} } \\  & & & \\ \hline
1 & \(-0.02\) & \(-0.86\) & \(0.84\) \\
2 & \(-0.05\) & \(-1.76\) & \(1.71\) \\
3 & \(-0.43\) & \(-1.17\) & \(0.74\) \\
4 & \(-0.33\) & \(-1.39\) & \(1.06\) \\ \hline \hline \end{tabular}
\end{table}
Table 6: Wind Pressure Difference between Windward and Leeward Surfaces in Winter.  
Figure 10 illustrates a distribution cloud map displaying outdoor windless zones, with green spots indicating locations with no wind. Windless zones are mainly found on the leeward side of buildings and in semi-enclosed or enclosed areas. Scenario 1, shown in Figure 11, has a windless zone size that is notably smaller, making up 5.13% of the total campus area. Scenario 4 features a windless zone area that is significantly larger than Scenario 1's, reaching 5.52%. Scenarios 2 and 3 feature greater areas with no wind, making up 9.60% and 8.32%, respectively. Scenario 1 is the most desirable based on the proportion of windless zone area.  
Figure 10: Distribution Map of Wind-Free Zone Distribution at a height of 1.5 m.  
Figure 9: Wind Speed Vector Map at a height of 1.5 Meters, Horizontal Plane.  
Figure 12 displays the average wind pressure difference between the inner and outer surfaces of the building's external windows. The Evaluation Standard for Green Building in China (GB/T50378-2019) requires that over 50% of a building's external windows must exhibit a wind pressure differential of over 0.5 Pa between the inner and outer surfaces in summer. Scenario 2's compliance ratio for external windows is 48.29%, falling short of the threshold. Nevertheless, the other three scenarios were all above the 50% criterion. Scenario 3 excels with a compliance ratio of 75.83% for its exterior windows. Scenario 1 has a compliance ratio of 50%, whereas Scenario 4 has a compliance level of 55.56%. Thus, adopting Scenario 3 for the project could result in improved indoor air quality in the summer.  
Figure 11: The proportion of the wind-free zone area to the total campus land area.