## 1 Introduction
### New Research Scheme Proposal  
By following the below-mentioned procedures, the proposed new research scheme can effectively discern the intertwined adverse effects for full-scale/model test comparisons for structures such as large cooling towers:  
_Step 1:_ Simultaneously measuring the meteorological wind data and wind effects on structures on the prototype and conducting corresponding model tests on the scaled models without the Re effects simulation in the traditional ABL wind tunnel;  
_Step 2:_ Creating a highly accurate (with the ABL turbulence characteristics accurately simulated according to the field measurement results) stationary ABL flow field at a low Re (flow field A) and a highly realistic non-stationary ABL flow field at a low Re (flow field B) on a CFD platform or in a multiple-fan actively controlled wind tunnel using measured meteorological wind data, and performing model tests in both flow fields;  
_Step 3:_ Compute the structural responses to wind loads in various flow fields, including flow fields A and B, the flow field simulated in the traditional ABL wind tunnel, and the realistic flow field;  
_Step 4:_ Compare wind-induced structural responses based on in situ measurements with those based on traditional wind tunnel model tests. This will help quantify the total discrepancies, including Re effects, turbulent flow characteristics effects, and non-stationarity effects. Then, analyze the structural responses based on model tests conducted in flow fields A and B to separate these adverse effects. Specifically, quantify Re effects by comparing structural responses for full-scale measurements to those for model tests conducted in flow field B. Non-stationarity effects should be quantified by comparing structural responses for the model test conducted in flow field A to those for the model test conducted in flow field B. Turbulent flow characteristics effects should be quantified by comparing structural responses for the model test conducted in flow field A to those for the traditional wind tunnel model test;  
_Step 5:_ Determine the most significant adverse influence on the reliability of the traditional ABL wind tunnel simulation technique by comparing the three adverse effects. Figure 1 showcases the flowchart of the new research scheme, which heavily relies on the abilities of the CFD technique and the multiple-fan actively controlled wind tunnel technique in simulating the non-stationary flow fields. Capabilities of CFD Technique and Multiple-Fan Actively Controlled Wind Tunnel Technique Reported in the Literature  
According to ref. [23], a flow field is simulated by inputting the inlet velocity varied in accordance with a non-stationary wind speed time-history measured near Shenzhen Baoan Stadium on the commercial CFD platform Fluent utilizing the user-defined function (UDF) module provided by the numerical platform. The pressure field on a low-rise building in that flow field is then calculated and compared with that calculated in a stationary flow field. When the numerical simulation is completed, the velocity samples calculated are not directly compared with the simulation target by ref. [23] to validate the simulation accuracy before use. With respect to the physical tests, the concept of actively controlled wind tunnels was first proposed in the 1970s, and some researchers have since realized flow control in wind tunnels to mitigate some issues with the traditional ABL wind tunnel simulation technique, such as low turbulence intensity and small-scale turbulence content. However,  
Figure 1: Flowchart of the new research scheme. most of these researchers relied on actively controlled devices placed at the beginning of the traditional wind tunnel to adjust the simulated flow, which technically falls under semi-actively controlled methods. To date, only researchers from Miyazaki University have realized actively controlled wind tunnel model tests in the true sense [24,25].