## 4 Results and Discussion
#### 4.1.3 Running Speed of the HST  
Figure 11 illustrates the changes in the aerodynamic load coefficients of a HST passing through a wind barrier with a porosity of 30% under a 15 m/s crosswind at different running speeds (200, 250, 300, and 350 km/h). Tables 5 and 6 provide the amplitude of changes in the aerodynamic load coefficients and the amplitude of the rate of changes in the aerodynamic load coefficients for the HST passes through the wind barrier at different running speeds. According to Figure 11, combined with Tables 5 and 6, it becomes apparent that as the speed of the HST increases, the aerodynamic load coefficients decrease. Additionally, the amplitude of changes in the aerodynamic load coefficients and the amplitude of the rate of changes in the aerodynamic load coefficients also decrease. For example, for the head car of the HST, when the train enters the wind barrier at a speed of 200 km/h, the amplitude of the change in the lift force coefficient and the amplitude of the rate of change in the lift force coefficient are 0.1094 and 0.3506, respectively. However, when the train enters the wind barrier at a speed of 350 km/h, the corresponding indicators of the head car are 0.0306 and 0.1738, respectively, decreasing by 72.03% and 50.43%. These results indicate that as the running speed increases, the degree of the sudden change in aerodynamic load during the HST entering or exiting the wind barrier area will be mitigated. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **Crosswind** \\ **Speed (m/s)** \\ \end{tabular} } & \multirow{2}{*}{**Carriage**} & \multicolumn{5}{c}{\(\Delta C_{\text{max}}^{{}^{\prime}}\)} \\  & & \(C_{D}\) & \(C_{L}\) & \(C_{M}\) & \(C_{D}\) & \(C_{L}\) & \(C_{M}\) \\ \hline \multirow{3}{*}{10} & Head & 0.3611 & 0.0860 & 0.0554 & 0.3349 & 0.0763 & 0.0480 \\  & Middle & 0.0449 & 0.0929 & 0.0034 & 0.0446 & 0.0829 & 0.0034 \\  & Tail & 0.0706 & 0.0800 & 0.0048 & 0.0709 & 0.0814 & 0.0083 \\ \hline \multirow{3}{*}{15} & Head & 0.5794 & 0.2220 & 0.0923 & 0.5269 & 0.1837 & 0.0797 \\  & Middle & 0.0829 & 0.1657 & 0.0106 & 0.0791 & 0.1871 & 0.0094 \\  & Tail & 0.1011 & 0.0857 & 0.0171 & 0.1146 & 0.0551 & 0.0183 \\ \hline \multirow{3}{*}{20} & Head & 0.7763 & 0.3989 & 0.1306 & 0.7617 & 0.3740 & 0.1120 \\  & Middle & 0.1746 & 0.1914 & 0.0269 & 0.1797 & 0.2446 & 0.0229 \\  & Tail & 0.1583 & 0.1463 & 0.0366 & 0.13 & 0.0691 & 0.0334 \\ \hline \multirow{3}{*}{25} & Head & 0.9594 & 0.5969 & 0.1686 & 0.9428 & 0.5597 & 0.1449 \\  & Middle & 0.2831 & 0.1614 & 0.0529 & 0.2237 & 0.1871 & 0.0477 \\ \cline{1-1}  & Tail & 0.2163 & 0.2114 & 0.0431 & 0.1723 & 0.1014 & 0.0511 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Amplitude of the rate of changes in aerodynamic load coefficients for the HST passes through the curved wind barrier at different crosswind speeds. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **Crosswind** \\ **Speed (m/s)** \\ \end{tabular} } & \multirow{2}{*}{**Carriage**} & \multicolumn{5}{c}{\(\Delta C\)} \\  & & \(C_{D}\) & \(C_{L}\) & \(C_{M}\) & \(C_{D}\) & \(C_{L}\) & \(C_{M}\) \\ \hline \multirow{3}{*}{15} & Head & 0.0824 & 0.0430 & 0.0117 & 0.0771 & 0.0396 & 0.0116 \\  & Middle & 0.0234 & 0.0566 & 0.0021 & 0.0233 & 0.0515 & 0.0021 \\  & Tail & 0.0211 & 0.0125 & 0.0042 & 0.0191 & 0.0113 & 0.0042 \\ \hline \multirow{3}{*}{20} & Head & 0.1116 & 0.0857 & 0.0146 & 0.1056 & 0.0830 & 0.0145 \\  & Middle & 0.0458 & 0.0517 & 0.0067 & 0.0438 & 0.0523 & 0.0063 \\  & Tail & 0.0329 & 0.0195 & 0.0106 & 0.0264 & 0.0071 & 0.0107 \\ \hline \multirow{3}{*}{25} & Head & 0.1467 & 0.1401 & 0.0184 & 0.1348 & 0.1398 & 0.0178 \\  & Middle & 0.0728 & 0.0362 & 0.0151 & 0.0696 & 0.0413 & 0.0150 \\ \cline{1-1}  & Tail & 0.0425 & 0.0427 & 0.0128 & 0.0367 & 0.0242 & 0.0139 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: _Cont._