Aerodynamics of Small-Scale Propellers Undergoing Dynamic Tilting Maneuvers

Small unmanned air vehicles (SUAVs) frequently perform rapid tilting maneuvers to transition between flight conditions or avoid obstacles. This study investigates the aerodynamic effects of three specific transitions: hovering to forward flight, climbing to forward flight, and forward flight to hovering. The analysis reveals that rapid maneuvers cause aerodynamic loads such as thrust and torque to deviate significantly from steady-state values while also inducing marked oscillations in the loads and substantial wake deformation. Due to its nonnegligible inertia, the wake cannot instantaneously adapt to the propeller’s position and orientation throughout the maneuver. This lag results in wake stretching or compression along the axial direction, which modifies the induced velocity on the blades and affects the resulting aerodynamic forces. These effects become more pronounced as the maneuver’s rapidity increases. The analyses are carried out using a midfidelity vortex particle method (VPM) solver applied to a low-Reynolds-number SUAV propeller. This meshless, Lagrangian approach efficiently captures complex vortical structures and wake interactions at low computational cost. The propeller blades are modeled using a lifting-line approach integrated into the VPM solver, making it an efficient tool for investigating dynamic propeller effects in SUAV performance evaluation and design.