A programmable simulator for reproducing urban low-altitude wind hazards

To address a core bottleneck in the development of Urban Air Mobility (UAM), namely the physical simulation of complex, dynamic low-altitude wind fields, this study successfully developed and validated the large-scale integrated simulation facility named “Wind-Matrix.” Through three integrated designs oriented toward low-altitude aircraft testing, the facility extends the application scope of existing multi-fan wind tunnels and extreme-wind-field simulators: (1) It uses a horizontal wind wall composed of 81 independently programmable high-speed axial-flow permanent magnet synchronous fans, enabling precise and rapid (sub-second) control of wind speed, wind shear, and gusts. (2) It integrates a movable vertical jet, a bottom swirl flow system, and the horizontal wind wall into a synchronized facility, allowing the stable reproduction of the complete evolution of extreme wind fields—such as tornadoes and downbursts—within a single experiment. (3) It enables precise generation of complex three-dimensional non-uniform flow fields, including sinusoidal distributions, through independent coordinated control of all 81 fans, with dynamic wind-field adjustment based on real-time feedback. Experimental results demonstrate that the platform can accurately generate maximum wind speeds of 55 m/s, customizable turbulence spectra, wind shear gradients, transient gusts, tornadoes and downbursts, successfully simulating multidimensional urban wind environments ranging from steady flows to unsteady composite flows. This work helps narrow the critical “data gap” between numerical simulation and real flight, providing an essential data foundation for aerodynamic testing, control system verification, and the establishment of safety standards for aircraft. It is expected to significantly advance the safety and engineering maturity of UAM technologies. Chen Zhao and colleagues developed and validated Wind-Matrix, a large-scale low-altitude Urban Air Mobility wind simulator with 81 programmable fans, vertical jet, and swirl system. It generates 55 m/s max winds, turbulence spectra, shear, gusts, tornadoes, downbursts, and 3D non-uniform flows, bridging the critical sim-to-flight data gap and supporting aerodynamic testing, control system verification, and safety standards.