## 3 Results and Discussions
### Evaluation of Aerodynamic Efficiency Using the Taguchi Method  
The numerical simulation results (CFD) are presented in Table 6. The table shows the combinations of rotor geometric parameters--diameter D and chord length c--as well as the averaged values of the torque coefficient Cm and the aerodynamic drag coefficient Cd obtained for the last, twentieth rotor revolution, after the system has reached steady state. The Cm/Cd ratio was also calculated for a quantitative assessment of the aerodynamic efficiency. In addition, the signal-to-noise ratio (S/N) values were determined using the Taguchi method: according to the criterion \"larger is better\" (S/NLB) for the coefficient Cm, and according to the criterion \"smaller is better\" (S/NSB) for the coefficient Cd. The obtained values allow an objective comparison of various combinations of geometric parameters and determination of the optimal rotor configurations. Figure 14 shows the average values of the torque coefficient Cm (blue columns) and the aerodynamic drag coefficient Cd (red columns) for all 20 combinations of geometric parameters generated according to the Taguchi orthogonal array. The abscissa axis shows the test numbers N corresponding to different combinations of rotor diameter and chord length. Figure 14: Average values of torque coefficients \(\mathrm{C_{m}}\) and resistance \(\mathrm{C_{d}}\) for all combinations of geometric parameters. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**N** & **D, m** & \begin{tabular}{c} **c,** \\ **m** \\ \end{tabular}  & \begin{tabular}{c} **Average \(\mathrm{C_{m}}\) Value** \\ \end{tabular}  & \begin{tabular}{c} **Average \(\mathrm{C_{d}}\) Value** \\ \end{tabular}  & \begin{tabular}{c} **C\({}_{\mathrm{m}}\)/\(\mathrm{C_{d}}\)** \\ \end{tabular}  & \ \begin{tabular}{c} \(\left(\frac{\mathrm{S}}{\mathrm{N}}\right)_{\mathrm{LB}}\) \\ \end{tabular}  & \begin{tabular}{c} \(\left(\frac{\mathrm{S}}{\mathrm{N}}\right)_{\mathrm{SB}}\) \\ \end{tabular}  \\ \hline
1 & & 0.2 & 0.050778932 & 0.069018 & 0.735735 & \(-\)49.1447 & 16.98327126 \\ \  
The analysis of the graph shows that the optimal combination is observed for option No. 10, where the rotor diameter is D = 3 m and the chord length is c = 0.4 m. This configuration demonstrates the most favorable ratio between a high C\({}_{\rm m}\) value and a moderate C\({}_{\rm d}\) value, which indicates its high aerodynamic efficiency. Figure 15 shows the dependence of the ratio of the torque coefficient C\({}_{\rm m}\) to the aerodynamic drag coefficient C\({}_{\rm d}\) on the combination number N, corresponding to different variants of geometric parameters formed on the basis of an orthogonal array. This characteristic reflects the aerodynamic efficiency of each configuration. The maximum value of the ratio Cm/Cd is observed with combination No. 10, which indicates the most effective combination of diameter and chord length among all the variants considered. To quantitatively assess the influence of geometric parameters on the aerodynamic efficiency of the wind turbine, the signal-to-noise ratio (S/N) values were calculated using the Taguchi method in accordance with Equations (9) and (10). The torque coefficient C\({}_{\rm m}\) was used as an output parameter for the S/NLB criterion, since its maximization contributes to an increase in the useful work of the rotor. For the S/N\({}_{\rm SB}\) criterion, the aerodynamic drag coefficient C\({}_{\rm d}\) was used, since its reduction leads to a decrease in losses and an increase in the overall efficiency of the plant. Calculation of the S/N\({}_{\rm LB}\) and S/N\({}_{\rm SB}\) values allowed us to identify the most effective combinations of geometric parameters and evaluate their stability to external disturbances.