## 3 Results  
### Impact of Opening Sizes  
#### 3.1.1 Results for Building Models with Varying Windward Opening Sizes  
The results obtained within the scope of the study are presented based on the mid-plane of the three-dimensional model, as exemplified in Figure 10. The dimensionless velocity and pressure contour results obtained for building models with fixed outlet opening size and varying inlet openings were shown in Figures 11 and 12, respectively. The results showed that the building models with larger inlet openings had lower air velocities and higher internal pressures. This confirmed the inverse relationship between velocity and pressure in accordance with [PERSON]'s principle. As seen in the results of the WO5 building model, the changes in the air velocity entering the building with a larger inlet  
\begin{table}
\begin{tabular}{c c c c c c} \hline Roughness Constant & C\({}_{\text{s}}\) = 0.3 & C\({}_{\text{s}}\) = 0.4 & C\({}_{\text{s}}\) = 0.5 & C\({}_{\text{s}}\) = 0.6 & C\({}_{\text{s}}\) = 0.7 \\ \hline (U/U\({}_{\text{ref}}\))\({}_{\text{max}}\) & 0.78 & 0.76 & 0.77 & 0.74 & 0.76 \\ \hlineopening size are milder compared to those in a building with a smaller opening size. In the case of the WO1 model, the smaller inlet opening limited the volume of air entering the building, leading to a sudden drop in the air velocity striking the windward wall. This resulted in a significant pressure increase around the opening. This pressure growth caused the air to enter the building model at a higher speed, which gradually decreased as the inlet opening size increased. With the increment in the inlet opening size, a rise in indoor air pressure was observed. While the large inlet opening allowed more air mass to enter the building, the fixed outlet opening caused a significant increase in the indoor pressure, especially from the WO3 model onwards. This demonstrates the effect of the inlet opening size on indoor pressure. Figure 11: Dimensionless velocity distributions of buildings with different windward opening configurations. (**a**) WO1, (**b**) WO2, (**c**) WO3, (**d**) WO4, (**e**) WO5. Figure 10: Contour plane at the center of the building model. Figure 13 shows the distribution of streamlines obtained for building models with fixed outlet opening sizes and variable inlet opening sizes. When examining the results, it is evident that a horseshoe vortex is formed in the lower part of all building models, regardless of the change in opening sizes. This result indicates the presence of a consistent flow pattern in front of the building. The airflow entering the building exhibited different flow structures in each model. In the WO1 building model, a counterclockwise vortex formed at the upper right corner of the building above the incoming jet, while a clockwise vortex formed at the lower right edge of the building. In the WO2 building model, the vortex that formed at the lower edge inside the building shifted to the left and became smaller. In the WO3 and WO4 building models, clockwise rotating vortices at the bottom of the incoming jet became more prominent. In the WO5 model, the large inlet opening allowed the incoming jet to reach the lower part of the building, thus preventing the formation of reverse flow in the lower region. Instead, a counterclockwise vortex formed at the upper part of the jet, near the center of the building. The air exiting the building formed a large reverse flow region after leaving it. The distribution in this reverse flow region was similar between the WO1 and WO2 building models, and similarities were also observed between the WO3 and WO4 models. In the WO5 building model, two large recirculation zones were prominent, both below and above the exiting jet. Figure 14 shows the change in wind speed ratio (\(\rm U/U_{ref}\)) along the horizontal line drawn along the windward and leeward window openings for building models with fixed outlet openings and different inlet openings, as a function of the distance ratio (x/D).