## 3 Open-Jet Testing  
Full-scale wind testing on buildings and other structures is ideal; however, achieving a 1:1 scale flow that accurately replicates genuine windstorm attributes poses significant challenges [27]. A facility that generates a 1:1 scale flow would necessitate immense blowers positioned at a distance surpassing what a practicable facility could accommodate. Synthetic wind exhibits substantial high-frequency turbulence and lack of low-frequency turbulence at higher Reynolds numbers, imposing restrictions on the size of vortices, thus rendering the scaling of buildings an inevitable requirement for realistically reproducing authentic physics. While there are testing capabilities encompassing large-scale residential structures, the flow characteristics introduce critical questions regarding their resemblance to full-scale ones [59]. Therefore, the scaling of test objects remains imperative for up-holding accurate physics. Concurrently, large-scale testing, albeit not full-scale, promises an enhancement in the Reynolds number and its associated aerodynamics. The evolution of large-scale wind testing has undergone various stages before attaining its current state [44; 60]. However, turbulence is fundamental for the understanding of aerodynamics, as well as for optimizing the performance of various systems [61]. In the pursuit of advancing capabilities in simulating the atmospheric boundary layer (ABL) and understanding the flow mechanism and aerodynamics responsible for the formation of peak loads that cause failure to buildings, the author led a research team to establish the Windstorm Impact, Science and Engineering (WISE) Laboratory, situated at Louisiana State University (LSU), and undertook the construction of a compact open-jet facility in 2013 [45; 60; 62] (Figure 3). The principle behind open-jet testing lies in its absence of physical enclosures, offering two primary advantages: (i) the generation of larger eddies, resulting in higher peak pressures akin to those observed at full scale, and (ii) a reduction in blockage effects [63]. The primary objective of this apparatus was to physically replicate hurricane-induced wind patterns resembling those encountered in open and suburban terrains. Reduced-scale replicas of low-rise structures were subjected to experimental scrutiny to ascertain the impact of approaching flow turbulence characteristics, scale considerations, and the proximity effect of the open-jet exit on the flow dynamics around low-rise buildings [45]. Additionally, the study delved into the alterations in separation bubble length occurring on the roof surface. Specifically, the investigation sought to elucidate  
Figure 3: Open-jet testing: (**a**) the central concept, and (**b**) small-scale open-jet at LSU. the correlation between these variables and the magnitudes of peak pressures exerted on the roof, as detailed in the author's previous studies [45; 60]. Employing a modifiable turbulence generation mechanism, diverse wind profiles were physically emulated. A multidisciplinary research team at LSU, comprising experts from Civil and Environmental Engineering, Mechanical Engineering, Coast and Environment, Louisiana Sea Grant, Geography and Anthropology, Construction Management, and Sociology, collaborated on a project entitled 'Hurricane Flow Generation at High Reynolds Number for Testing Energy and Coastal Infrastructure', which received funding from the Louisiana Board of Regents [64]. The objective was to establish an extensive hurricane testing facility. This facility facilitates the production of high Reynolds number wind flows over a test section measuring 4 m \(\times\) 4 m (see Figure 4). These capabilities empower the execution of wind engineering experiments at a notably large scale. Furthermore, the generously sized open-jet facility possesses the potential for conducting destructive testing on models constructed from authentic construction materials. Blockage is minimized as per the principles of open-jet testing [63].