# Wind Loads on a Solar Panel at High Tilt Angles
## 3 Results and Discussion  
### Longitudinal Pressure Distributions  
The \(C_{p}\) distributions on the centerline (\(y\)/\(W\) = 0.5) for \(\beta\) = 0\({}^{\circ}\) are shown in Figure 3. The origin of the coordinates (\(\chi\)/L = 0 and \(y\)/\(W\) = 0) is located at the left corner of the tilted panel. The solid and hollow symbols represent the value of \(C_{p}\) on the upper and lower surface, respectively. Suction, which corresponds to flow separation, is observed on the upper surface for all of the test cases. For \(\alpha\) = 30\({}^{\circ}\), the value of \(C_{p}\) decreases significantly near the front edge, reaches a peak value of \(-\)1.66, and approaches a more moderate level in the second half of the panel. At larger angles of tilt (\(\alpha\geq 50^{\circ}\)), there are flattened \(C_{p}\) distributions, for which the value of \(C_{p}\) (\(-\)0.72 to \(-\)0.82) for a specific value of \(\alpha\) varies by less than 4%. On the lower surface, there is a slight expansion near the front and rear edges for \(\alpha\) = 10\({}^{\circ}\). Positive pressure is observed and the magnitude increases as \(\alpha\) increases. This shows that the localized load is the most significant near the front edge for \(\alpha\) = 30\({}^{\circ}\). There is also a slight variation in the magnitude of \(C_{p}\) (0.91 to 0.93) for \(\alpha\) = 50\({}^{\circ}\)-80\({}^{\circ}\), so the uplift lift force is approximately constant for larger angles of tilt (\(\alpha\geq 50^{\circ}\)), when \(\beta\) = 0\({}^{\circ}\).  
The \(C_{p}\) distributions for \(\beta\) = 30\({}^{\circ}\), 45\({}^{\circ}\), and 135\({}^{\circ}\) are shown in Figures 4-6. These correspond to the most common direction for the wind for the meteorological data. For \(\beta\) = 30\({}^{\circ}\) and 45\({}^{\circ}\), there is greater suction on the upper surface for \(\alpha\) = 10\({}^{\circ}\) and 20\({}^{\circ}\). A flow expansion in the second half of the panel is also observed, particularly for \(\beta\) = 45\({}^{\circ}\). This agrees with the results of [PERSON] et al. [12]. Suction near the front edge is mitigated for \(\alpha\) = 30\({}^{\circ}\), and there is a flatter \(C_{p}\) distribution. The value of \(C_{p}\) is approximately the same for \(\alpha\) = 40\({}^{\circ}\)-80\({}^{\circ}\) (\(-\)0.701 to \(-\)0.711), and the effect of \(\alpha\) is minimal. Its amplitude increases slightly more than that for \(\beta\) = 0\({}^{\circ}\) (\(C_{p}\) = \(-\)0.743 to \(-\)0.756). For \(\beta\) = 135\({}^{\circ}\), a small degree of suction is observed near the front face, and the value of \(C_{p}\) increases downstream. The value of \(\alpha\) has an obvious effect, in that the amplitude of \(C_{p}\) increases as \(\alpha\) increases. There is a slight flow expansion near the rear edge for \(\alpha\) = 10\({}^{\circ}\) and 20\({}^{\circ}\). On the lower surface for \(\beta\) = 30\({}^{\circ}\) and 45\({}^{\circ}\), there is a fairly uniform \(C_{p}\) distribution for specific values of \(\alpha\). The value of \(C_{p}\) is positive, except for the case of \(\alpha\) = 10\({}^{\circ}\) near the rear edge. This shows that the uplift force increases as \(\alpha\) increases. Suction on the lower surface for \(\beta\) = 135\({}^{\circ}\) produces greater downward force, particularly for \(\alpha\geq 30^{\circ}\).  
Figure 3: Mean longitudinal pressure distributions at \(y\)/\(W\) = 0.5; \(\beta\) = 0\({}^{\circ}\).  
Figure 4: Mean longitudinal pressure distributions at \(y/W=0.5\); \(\beta=30^{\circ}\).  
Figure 5: Mean longitudinal pressure distributions at \(y/W=0.5\); \(\beta=45^{\circ}\).  
Figure 6: Mean longitudinal pressure distributions at \(y/W=0.5\); \(\beta=135^{\circ}\).