# Effects of Wind Barrier Porosity and Inclination on Wind Speed Reduction
## 3 Results  
Case A (Porosity of 0% with Inclinations of 90\({}^{\circ}\), 80\({}^{\circ}\), and 70\({}^{\circ}\))  
Table 1 shows variations in the decrease in average wind velocity at different distances for a wind barrier of 0% porosity at three different inclinations (90\({}^{\circ}\), 80\({}^{\circ}\), and 70\({}^{\circ}\)), and Figure 4 shows the visualization of the spatial distribution of the average wind velocity according to distance. For each inclination, the correlation between the distance and average wind speed decrease was statistically significant at \(\alpha\) = 0.05 (90\({}^{\circ}\): F-value = 24.618, \(p\) < 0.001; 80\({}^{\circ}\): F-value = 23.185, \(p\) < 0.001; 70\({}^{\circ}\): F-value = 22.232, \(p\) < 0.001). The decrease in wind velocity for all inclinations was statistically significant up to six times (Table 1). The decrease in wind velocity differed slightly at each sample point according to the inclinations. The reduction ratio of the wind velocity for each inclination decreased as the distance increased, indicating a difference in the wind protection range (Table 1, Figure 4). The range of the reduction ratio also varied: 41-90% for 90\({}^{\circ}\), 34-90% for 80\({}^{\circ}\), and 37-90% for 70\({}^{\circ}\). Among these different inclinations, the 90\({}^{\circ}\) vertical had a large decreasing effect for the greatest distance of 600 cm (Table 1). \begin{table}
\begin{tabular}{c c c c c} \hline
**Porosity (\%)** & **Inclination (\({}^{\circ}\))** & **Distance (cm)** & **Height (cm)** & **Velocity (m/s)** & **Wind Reduction Ratio (\%)** \\ \hline  & \(-10\) (C) & 30, 60, 90 & 5.000 \(\pm\) 0.000  & 90 \\ \cline{3-5}  & 100 & 30, 60, 90 & 0.757 \(\pm\) 0.756  & 79 \\ \cline{3-5}  & 300 & 30, 60, 90 & 1.178 \(\pm\) 0.365  & 72 \\ \cline{3-5}  & 500 & 30, 60, 90 & 2.064 \(\pm\) 1.340  & 41 \\ \cline{3-5}  & \multirow{3-5}{*}{80\({}^{\circ}\)} & \(-10\) (C) & 30, 60, 90 & 5.000 \(\pm\) 0.000  & 77 \\ \cline{3-5}  & 400 & 30, 60, 90 & 1.434 \(\pm\) 0.162  & 59 \\ \cline{3-5}  & 600 & 30, 60, 90 & 2.969 \(\pm\) 1.400  & 88 \\ \cline{3-5}  & \multirow{3-5}{*}{80\({}^{\circ}\)} & \(-10\) (C) & 30, 60, 90 & 1.147 \(\pm\) 0.614 [FOOTNOTE:]Footnote : (C) represents the windward control point of wind speed. Wind velocity (m/s)Case B (Porosity of 25% with Inclinations of 90\({}^{\circ}\), 80\({}^{\circ}\), and 70\({}^{\circ}\))  
Table 2 shows the change in the average decrease in wind velocity according to distance for a porosity of 25% of a wind barrier with different inclinations (90\({}^{\circ}\), 80\({}^{\circ}\), and 70\({}^{\circ}\)), and Figure 5 shows the visualization of the spatial distribution of the average wind velocity according to distance. For each inclination, the correlation between the distance and decrease in average wind speed was statistically significant at \(\alpha\) = 0.05 (90\({}^{\circ}\): F-value = 17.851, \(p\) < 0.001; 80\({}^{\circ}\): F-value = 25.882, \(p\) < 0.001; 70\({}^{\circ}\): F-value = 22.817, \(p\) < 0.001). Similar to the wind barrier with a porosity of 0%, the decreasing wind velocity effect for all inclinations was found to be up to six times greater. The reduction ratio of the wind velocity for each inclination of the wind barrier with a porosity of 0% decreased with increasing distance. In contrast, the reduction ratio for each inclination of the wind barrier with a porosity of 25% increased with increasing distance and then gradually decreased (Table 2, Figure 5). This indicates that the wind velocity differs with porosity. The wind velocity differed slightly from each measured point, according to the inclinations. The range of the reduction ratio varied with the inclination of the wind barrier, 38-69% for 90\({}^{\circ}\), 33-67% for 80\({}^{\circ}\), and 42-62% for 70\({}^{\circ}\), indicating that inclinations played a considerable role in affecting wind velocity. The highest protection against wind was found to be provided by the inclination of 90\({}^{\circ}\).