Aerodynamic Characterization of a Fan-Array Wind Generator

Experimental assessment of safe and precise flight control algorithms for unmanned aerial vehicles under gusty wind conditions requires the capability to generate a large range of velocity profiles. In this study, we employ a small fan-array wind generator that can generate flows with large spatial and temporal variabilities. We perform a thorough aerodynamic characterization, operating the fans uniformly from low to maximum levels. Particle image velocimetry and hot-wire measurements indicate a jetlike flow with a nearly uniform core, which monotonously contracts in the streamwise direction and the surrounding, growing unsteady shear layers. These complex dynamics result in a limited region with a desired flow profile and turbulence level. The experimental results shed light on the flow generated by a full-scale fan-array wind generator, and they indicate the need for further improvements via properly designed add-ons and dedicated control algorithms.