## 5 Analysis and Discussion of Influence of Wind Resistance on Athletes
### Analysis of Wind Resistance Reduction of Optimized Sliding Route  
According to the CFD numerical simulation results of the NSC under different climatic conditions, the wind resistance reduction of the optimized sliding route, the WRDUI, and the TS were calculated based on Formulas (18)-(21). The calculation results are shown in Tables 5 and 6. At the same time, the fitting curves of the WRDUI and the TS with the change in the outdoor wind level were established according to Formulas (23) and (24). The fitting curves are shown in Figures 13 and 14.  
\[{\rm C}^{\rm b,d}=\left\{\begin{array}{ll}-0.0366+0.02574{\rm d}-0.0047{\rm d }^{2}+3.65477{\rm\times}{10^{-4}}{\rm d}^{3},{\rm b}=1\\ -0.01603+0.0071{\rm d},\quad\quad\quad\quad\quad\quad\quad  
Figure 14: Fitting curve of TS.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**S\({}^{\text{b,d}}\)(s)**} & \multicolumn{5}{c}{**Wind Direction**} \\ \cline{2-6}  & **WNW** & **NW** & **NWN** & **Mean Value** \\ \hline  & 3.125 & 0.02 & 0.02 & 0.03 & 0.02 \\  & 3.5 & 0.03 & 0.03 & 0.04 & 0.03 \\  & 4.5 & 0.04 & 0.03 & 0.05 & 0.04 \\ Wind level & 5.5 & 0.05 & 0.06 & 0.08 & 0.06 \\  & 6.5 & 0.09 & 0.08 & 0.11 & 0.09 \\  & 7.5 & 0.11 & 0.10 & 0.12 & 0.11 \\  & 8.229 & 0.16 & 0.12 & 0.14 & 0.14 \\ \hline \hline \end{tabular}
\end{table}
Table 6: The time saved of the optimized sliding route (TS).  
Figure 13: Fitting curve of WRDUI.  
It can be seen from Appendix A (Table A4) and Table 6 that with an increase in wind level (3.125, 3.5, 4.5, 5.5, 6.5, 7.5, 8.229), the optimized sliding route can reduce the air resistance by 0.2607 N, 0.3415 N, 0.4600 N, 0.6469 N, 0.9283 N, 1.1741 N, and 1.4535 N on average. According to Formula (21), the performance of athletes weighing 77 kg can be improved by 0.02 s, 0.03 s, 0.04 s, 0.06 s, 0.09 s, 0.11 s, and 0.14 s, respectively.  
The bar graph in Figure 13 shows that, regardless of the wind direction, as the wind level increases, the average wind resistance reduction of the optimized sliding route (AWRDU) increases.  
From Formula (23) and the fitting diagram in Figure 13, it can be seen that as the wind level increases, the wind resistance reduction index of the optimized sliding route (WRDUI) increases. It increases in a curve when the wind direction is WNW, and increases linearly when the wind directions are NW and NWN, with growth rates of 0.0071 and 0.00718, respectively.  
From Formula (24) and Figure 14, it can be seen that as the wind level increases, the time saved of the optimized sliding route (TS) increases accordingly. It increases in a curve when the wind direction is WNW, and increases linearly when the wind directions are NW and NWN, with growth rates of 0.01941 and 0.02176, respectively.  
These results also show the following:  
(1) When the climatic conditions during the competition are more complex, or the wind level around the venue is higher, the optimized sliding route can reduce the wind resistance more, thereby enabling athletes to achieve relatively better competition results.  
(2) In addition, the results also show that the shape and track design of the NSC are reasonable, so it can still effectively reduce the sliding wind resistance of athletes under complex climatic conditions.