Temporal and Spatial Propellor Wake Decay for Rotary Uncrewed Systems

The past 50 years of development have allowed uncrewed aerial vehicles to become more cost efficient and accessible, thereby allowing for greater use and applications. This increase in usage will ultimately lead to a greater density of vehicles causing more interactions with other vehicles' wake. The potential challenges to greater wake interactions can lead to decreased vehicle stability and efficiency; the mission payload can also see impact from wake interaction leading to noisy or erroneous data. There has been significant research for crewed aircraft wake decay, but there is still a need for research on small UAV operation as aspects like urban air mobility, UAV swarm application, and usage for atmospheric measurements increase. One key difference between the crewed and uncrewed flights is the prevalent use of rotary vehicles like quad and hex rotors that provide greater control and flexibility for payloads like sensors for research or packages for delivery. This research was conducted to better understand propellor wake decay for rotary vehicles and the wake effects that can be applied to path planning for urban mobility or swarms to optimize vehicle spacing. The experiments measured thrust on the propellor while observing turbulence of the wake at varying radial distances along the x and z-axis using both a five-hole probe and mini-x hotwire anemometer, and the effects of a partial or complete blockage of the wake propagation and its effects on the wake decay time and distance were measured and explored.