Streamwise gust alleviation: vortex flow modification using a rotating, swept tip on a rectangular wing*

Drones and micro-air vehicles may often experience adverse weather conditions such as gusts, since these vehicles fly at low altitudes and through various landscapes. One of the key aerodynamic features of gusts is flow separation. We explore dynamic wing planform change for mitigating streamwise gusts where the velocity increase/decrease with time is a step function. A swept tip panel on a rectangular wing rotates inward during step-up gusts and outward during step-down to counter the gust effects. A quantitative flow measurement, Shake-the-Box is performed to investigate the unsteady gust flow around the AR = 4 wing and how it changes with the tip-panel actuation. The modification in vorticity field found from the experiment further justifies the load changes on the wing.