## 3 Numerical Calculation Results and Analysis
### Comparison of Numerical Simulation Results with Wind Tunnel Test Results
When two antennas are in arrangement form 2, from 0\({}^{\circ}\) to 120\({}^{\circ}\) wind directions, the fluctuations in the overturning force coefficient and overturning moment coefficient curves are relatively mild, but they increase rapidly from 120\({}^{\circ}\) to 180\({}^{\circ}\), reaching their maximum values at 180\({}^{\circ}\). Compared to the bare tower condition without antennas, the overturning force coefficient and the overturning moment coefficient increased by 14.7% and 26.4%, respectively. When two antennas are in arrangement form 3, the tower's overturning force coefficient and overturning moment \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Research Method** & \begin{tabular}{c} \(C_{D}\) **at 0\({}^{\circ}\) Wind** \\ **Direction** \\ \end{tabular} & \
\begin{tabular}{c} \(C_{D}\) **at 30\({}^{\circ}\) Wind** \\ **Direction** \\ \end{tabular} &
\begin{tabular}{c} \(C_{D}\) **at 60\({}^{\circ}\) Wind** \\ **Direction** \\ \end{tabular} \\ \hline Numerical simulation & 0.8241 & 0.8254 & 0.7729 \\ Wind tunnel test & 0.8289 & 0.8565 & 0.7481 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison of the drag coefficients of the telecommunication tower obtained from wind tunnel tests and numerical simulations. coefficient reach their maximum values at wind directions of 60\({}^{\circ}\) and 120\({}^{\circ}\), and for most wind directions, both coefficients are higher than those of the other two arrangement forms. Figure 11: Variation curve of wind load on the telecommunication tower with wind direction when 2 antennas are arranged. (**a**) Drag coefficient. (**b**) Windward base overturning moment coefficient. (**c**) Lateral force coefficient. (**d**) Crosswind base overturning moment coefficient. (**e**) Overturning force coefficient. (**f**) Overturning moment coefficient. Figure 12 shows the flow fields at the mid-height cross-section of the antennas for three different arrangement forms when two antennas are arranged in a single layer. When the circular end of the antenna faces the wind, the wake region is small, resulting in a lower overturning force coefficient; when the flat end of the antenna faces the wind, the wake region noticeably enlarges, causing an increase in the overturning force coefficient. When two antennas are arranged in form 1, as shown in Figure 12a, within the \(0^{\circ}\) to \(60^{\circ}\) wind direction range, both antennas are located upstream of the tower cylinder, and with their circular ends facing the wind. The tower cylinder disrupts the wake and vortex formation area of the antennas. The upstream antenna significantly obstructs the inflow toward the tower cylinder, and its wake alters the characteristics of the flow, impacting the tower cylinder. At a \(30^{\circ}\) wind direction, relative to the inflow direction, one antenna is directly in front of the tower cylinder with a small gap, causing the antenna's separation shear layer to attach to the downstream tower cylinder, significantly reducing the flow velocity in the gap and, thus, decreasing the overturning force coefficient on the telecommunication tower. At a \(90^{\circ}\) wind direction, relative to the inflow direction, one antenna is directly in front of the other, and due to the small gap, they are also in a shear layer reattachment state, resulting in a reduction of the overturning force coefficient on the tower. In the \(120^{\circ}\) to \(180^{\circ}\) wind direction range, the tower cylinder is upstream of the antennas, and with the flat end of the antennas facing the wind, the wake region enlarges significantly, leading to a greater overturning force coefficient. At a \(150^{\circ}\) wind direction, relative to the inflow direction, the tower cylinder is directly in front of one antenna, causing the tower cylinder's separation shear layer to attach to the surface of the downstream antenna, resulting in a reduction of the overturning force coefficient on the tower.