Aerodynamic characterization of a wind generator with 40 × 40 individually controllable fans

This study presents an aerodynamic characterization of a fan-array wind generator (FAWG) operating at Reynolds number of 2.8×106 in a large room. The performance of unmanned aerial vehicles needs to be tested for a wide range of spatiotemporal wind conditions. For this purpose, we have built a FAWG with 40 × 40 individually controllable fans, covering a wind section of 3.25 m × 3.25 m with speeds up to 13 m/s. This wind section is monitored with an equidistant 8 × 8 pitot tube array and a hot-wire anemometer for different levels of uniform blowing. The flow has a nearly uniform core region, which shrinks similar to the potential core of a jet. Similar observations have been presented for a small FAWG [Li et al., “Aerodynamic characterization of a fan-array wind generator,” AIAA J. 62(1), 291–301 (2024)]. The wind velocity in the flow direction is observed to increase linearly with the duty cycle of the pulse width modulation signal employed to command the fan rotation speed. We demonstrate one key advantage of FAWG: it can modulate the wind velocity within 2 s.