Performance Insights of Thrust-Vectoring Distributed Propulsion Systems Using Off-Body Velocity Fields

Increasing interest in distributed electric propulsion architectures has ignited further research into the mechanisms of powered lift. A series of wind tunnel experiments were conducted throughout the current study using a quasi-two-dimensional, over-wing distributed propulsion configuration. Off-body velocity distributions in the propulsive wake and above the model upper surface were measured using particle-image velocimetry for several combinations of system angle-of-attack, fan thrust, and thrust-vectoring flap deflection angle. Examination of these velocity fields revealed the importance of supercirculatory coupling between the propulsive wake and model leading-edge bound circulation magnitude. Additionally, the variation in the size of the propulsive capture streamtube validated flow separation effects observed aft of the model, while also illustrating the multiple ways such a system can generate large lift coefficients. Overall, these results reinforce the recent developments towards understanding the physical reasons for the aerodynamic performance of distributed propulsion systems and vectored thrust.