Wind Tunnel Measurement of the Urban Wind Field for Flight Path Planning of Unmanned Aerial Vehicles

The focus of the present paper is the investigation of the wind field along the flight path of a small fixed-wing unmanned aerial vehicle (UAV) in an urban environment. The considered mission is a goods delivery as part of a last-mile logistics system. A representative downtown environment of a typical European city is studied. As was recently shown, the local wind field between the buildings can be exploited to obtain energy optimal flight paths for a UAV. So far these results are solely based on numerical simulations. In this paper, the numerical simulations of the wind field are supplemented and verified by wind tunnel experiments. For the wind tunnel tests a 1:100-scale model of the benchmark environment is used. Velocity profiles are measured with hot-wire probes and a five-hole pneumatic probe at several positions along the flight path. The latter is used to detect the flow direction. A combination of aerodynamic alignment and multi-zone approach for calibration is used to determine the local wind vectors. Further attention is paid to the turbulence and gustiness of the local flow. The present work constitutes an important step in the evaluation of the exploitation potential of local wind effects on UAV flight path planning.