Generation of Large-Scale Gust Structures in a Large Boundary Layer Wind Tunnel: 3D Flow Measurement Experiments

Wind-induced damage to roof components of buildings is mainly initiated by extreme suction pressures caused by vortices that develop when the oncoming wind flow impinges on the structure, resulting in flow detachment near roof corners and edges. Previous studies have demonstrated the effectiveness of several roof load mitigation strategies for alleviating uplift roof pressures under a limited set of idealized turbulent flow conditions. This project leveraged a flow-control instrument, Flow Field Modulator (FFM), at the University of Florida Natural Hazards Engineering Research Infrastructure (NHERI) Experimental Facility to actively generate a wider range of turbulent flow conditions in a large boundary layer wind tunnel (BLWT). The FFM is a 2D multi-fan array comprising 319 modular hexagonal aluminum cells with shrouded three-blade co-rotating propellers. The system enabled the active generation of large-scale turbulent structures by recreating user-specified velocity time signals to inject slowly varying fluctuations into wind tunnel flows. The project aimed to overcome ongoing limitations in traditional wind tunnel modeling approaches by enabling active and precise control of large wind gust structures to evaluate their impact on civil infrastructure.