# Wind Pressure Coefficient on a Multi-Storey Building with External Shading Louvers
## 4 Results and Discussion
### Features of Local Wind Pressure Coefficient along Measurement Lines
#### 4.2.2 Local Wind Pressure Coefficient on W-S-L Lines  
Figure 13a,b present the local range \(R\), local and average value of wind pressure coefficient \(C_{\rm p}\) on the central lines of the first floor along the windward, the lateral and the leeward surfaces. The windward surface suffers the largest fluctuation of \(C_{\rm p}\), while the lateral wall has the smallest fluctuation of \(C_{\rm p}\). Generally speaking, the windward surface has the widest \(R\) and the largest difference of the local \(C_{\rm p}\) along the central line. The leeward surface has the smallest \(R\) along the central lines. The \(C_{\rm p-max}\) line and the \(C_{\rm p-min}\) line have the similar shape and tendency. The maximum value and the \(C_{\rm p-min}\) are 0.55, and \(-\)0.44, respectively. On the windward surface, the largest \(R\) locates at 0.38\(h_{0}\) and the smaller \(R\) locates on the edge between the windward and the lateral surfaces. On the lateral surface, the \(R\) increases slightly along 0.5-0.8\(h_{0}\), then within 0.8-1.2\(h_{0}\) the \(R\) are almost the same. From 1.2\(h_{0}\) to 1.4\(h_{0}\), the \(R\) increases obviously, then it decreases again near the edge between the lateral surface and the leeward surface. On the leeward surface, the local \(C_{\rm p}\) increases obviously but the \(R\) just increases slightly.  
Figure 13c-j present the local range \(R\), local and average value of wind pressure coefficient \(C_{\rm p}\) on the central lines of the F2-F5 along the windward, the lateral and the leeward surfaces. Generally speaking, the tendencies of the \(C_{\rm p-max}\) and \(C_{\rm p-min}\) along the central lines on different floors are similar to those on F1. The maximum value on the \(C_{\rm p-max}\) line is larger when the floor is higher, except for F5, on which the maximum value on the \(C_{\rm p-max}\) line is a little smaller than those on F4. The minimum value on the \(C_{\rm p-min}\) line is lower when the floor is higher. The locations of the minimum value on the \(C_{\rm p-min}\) lines are on the lateral surface for all floors. However, for F1 and F2, the locations are near edge of the windward surface at around 1.4\(h_{0}\), while for the higher floors, \(C_{\rm p}\) near the edge of the leeward surface at around 0.55\(h_{0}\) is the minimum value on the \(C_{\rm p-min}\) lines. On the windward surface, the \(R\) along the central lines is wider for the higher floors. The absolute gradient of the \(C_{\rm p-max}\) line becomes lower near the central vertical lines but becomes higher near the edge of the lateral surface. On the lateral surface, the \(R\) becomes wider at around 0.55\(h_{0}\) for the higher floors because of the lower \(C_{\rm p-min}\). Along the lines on the lateral surface, the location of the minimum \(R\) becomes closer to the windward surface, as the floor becomes higher. The fluctuation of \(R\) near the edge of the leeward surface becomes smooth. This phenomenon means that as the floor gets higher, the wind suction effect of reverse flow becomes greater than the effect of the backward recirculation, but the negative pressure area, caused by the reverse flow, seems to be smaller than the negative pressure area caused by recirculation. On the leeward surface, the \(R\) along the central lines are similar for F1, F2 and F3, while the \(R\) are a little wider for F4 and F5. The absolute gradient of \(C_{\rm p}\) becomes lower for the higher floors, which means that higher floors are prone to have smoother \(C_{\rm p}\) distribution along these lines.  
Figure 13: _Cont._Figure 13: _Cont._