## 3 Results and Discussion  
### Analysis of Aerodynamic Coefficients  
After acquiring the aerodynamic forces by a six-component force balance, the mean values (i.e., \(C_{l}\_\)mean, \(C_{d}\_\)mean, and \(C_{m}\_\)mean) and the fluctuations (i.e., \(C_{l}\_\)rms, \(C_{d}\_\)rms, and \(C_{m}\_\)rms) of the instantaneous aerodynamic force coefficients were obtained through statistical analysis. In the present study, \(C_{d}\_\)mean was measured to be 0.061 at a wind attack angle of \(0^{\circ}\), which is close to the result of 0.064 from [PERSON] et al. [4] and the numerical simulation result of 0.060 from [PERSON] [30]. Figure 5 shows the mean values of the lift, drag, and moment coefficients for all test models at wind attack angles ranging from \(-20^{\circ}\) to \(20^{\circ}\). The reduction of aerodynamic coefficients is defined as:  
\[\textit{reduction}=\textit{Case}\,0-\textit{Case}\,i(i=1,2,3,4,5) \tag{4}\]  
Figure 5: Comparison of mean aerodynamic force coefficients between five control cases and Case 0 at different wind attack angles. (**a**) \(C_{l}\_\)mean; (**b**) \(C_{d}\_\)mean; (**c**) \(C_{m}\_\)mean. When reduction is close to zero, it means this modification has little effect on the Case 0 model. For the mean drag coefficient, the five control cases are close to the Case 0, although there is a small difference at a large negative attack angle (e.g., \(-20^{\circ}\)). With respect to the mean lift coefficient, control cases 2-5 achieved a small reduction while the Case 1 had no distinct change compared with the Case 0 at negative attack angles. For this mean lift coefficient, the control cases 2-4 also had a reduction, while control cases 1 and 5 were close to Case 0 at positive attack angles. For the mean moment coefficient at negative attack angles, control cases 2-5 achieved a decrease and Case 1 had no noticeable change in comparison with Case 0. At positive attack angles, Case 5 was close to Case 0, while the other control cases achieved a distinct decrease. Figure 6 illustrates the fluctuations (RMSs: root-mean-square values) of the lift, drag, and moment coefficients for all test models at the wind attack angle range of [\(-20^{\circ}\), \(20^{\circ}\)]. At a large negative attack angle (e.g., \(-20^{\circ}\)), the control effectiveness of the five control cases is [17.91%, 70.16%, 71.41%, 83.73%, 18.81%]; [16.32%, 66.73%, 68.65%, 93.15%, 6.59%]; and [4.13%, 59.45%, 61.52%, 65.28%, 25.22%] for the lift, drag, and moment coefficient RMSs, respectively. Control cases 2-4 had a large decrease in the RMSs of the aerodynamic coefficients, while Case 4 had the best control effectiveness. Cases 1 and 5 had a small control effectiveness, because the suction/jet holes were only located on the upper or lower surfaces. For Case 0 at positive attack angles, the peaks appear at the angle of \(15^{\circ}\) for the lift and drag coefficients, with the maximum value occurring at the angle of \(10^{\circ}\). For the peak value suppression at the angle of \(15^{\circ}\), the control effectiveness of the five control cases is [7.04%, 19.29%, 12.38%, 23.25%, 8.53%]; [9.32%, 15.65%, 9.09%, 18.76%, 5.91%]; and [15.00%, 24.98%, 25.57%, 25.55%, 7.37%] for the lift, drag, and moment coefficient RMSs, respectively. Control cases 3 and 4 are better than the other control cases. Combining the control effectiveness at the angles of \(-20^{\circ}\) and \(15^{\circ}\), Case 4 should be the best control case. Following this, the integral of the \(C_{m\_}\)mean along a wind attack angle from \(-20^{\circ}\) to \(20^{\circ}\) was performed to evaluate the work done by the moment (Table 2). The results indicate that control cases 2-4 had smaller values compared to Case 0, while Case 4 had the smallest value, which indicates the best control effectiveness. Figure 6: Comparison of aerodynamic force coefficient fluctuations between five control cases and Case 0 at different wind attack angles. (**a**) \(C_{l\_}\)rms; (**b**) \(C_{d\_}\)rms; (**c**) \(C_{m\_}\)rms.