## 3 Comparison Based on Numerical Simulation
### Model Tests Conducted in TJ-3 Wind Tunnel  
Two pressure measurement model tests are conducted in the TJ-3 passive wind tunnel of Tongji University, with flow fields simulated using the ABL empirical formulae listed in codes and monographs and the ABL wind velocity field measured on location, respectively.  
Figure 6: Original non-stationary velocity sample and simulated senior sinusoidal function.  
The flow field simulated using the ABL empirical formulae is regarded as the flow field for the traditional ABL wind tunnel model test, while the flow field simulated based on the ABL wind velocity field measured on location is regarded as flow field A. It should be emphasized that this simulation approach for flow field A employing a passive wind tunnel is different from the planned simulation method of utilizing a CFD platform or an actively controlled wind tunnel for the proposed research scheme (see Section 2) as the former is more economical and comparatively more effective.  
The TJ-3 wind tunnel is a closed-circuit rectangular cross-section wind tunnel, wherein the size of the test section is 15 m in width, 2 m in height, and 14 m in length. The test wind speed can be continuously controlled in the 1.0 to 17.6 m/s range. The non-uniformity of the wind speed of the flow field in the test zone is less than 1%, the turbulence intensity is less than 0.5%, and the average flow deviation angle is less than 0.5\({}^{\circ}\). Ref. [28] observes that the empirical turbulence intensity profile is noticeably greater than the field measurement data over the entire height. Therefore, the two flow fields mentioned above are simulated differently by adjusting the position and number of roughness elements and spires placed at the start of the wind tunnel work section (Figure 9a). After many attempts, both flow fields are simulated in the TJ-3 wind tunnel. Then, the pressure measurement model and the surroundings are modeled on a geometric scale of 1:200 using synthetic glass (see Figure 9b), and the pressure measurement tests are undertaken to measure wind effects on the tower model in the two flow fields.  
Figure 8: Pressure coefficient time-histories calculated at 0, 90, and 180 degrees on the circular object.  
Figure 7: Velocity contours obtained at end of duration (unit: m/s).  
The 36 \(\times\) 12 taps are arranged on 12 vertical sections and in 36 horizontal circular directions for the pressure-measuring tower model. DSM3000 electronic pressure scanners of Scanivalve Corp. are used to obtain the wind pressures on the tower surfaces. The signal data are acquired at a sample rate of 312.5 Hz, and the sample length is 6000 data at one tap in each run. Without the aid of sufficient sticking paper belts along the vertical direction, the actual static characteristics of the prototype cooling tower at high Re are not simulated in the reduced-scale model. The turntable rotates from 0\({}^{\circ}\) to 360\({}^{\circ}\) at 22.5\({}^{\circ}\) intervals, but only the case with the same wind direction as that observed in the field on 29 November 2011 is considered, so the wind effects obtained from the model tests can compare with the full-scale results. The results obtained will be referred to as the data for the traditional ABL flow field and those for flow field A, respectively, for subsequent analyses.