Aerodynamic characteristics analysis of the transitional state of foldable-wing UAVs

Abstract This study is based on the Multiple Reference Frame (MRF) method to construct a numerical simulation model of the transition state of a folding wing vertical takeoff and landing unmanned aerial vehicle, and to investigate the influence of propellers on the aerodynamic characteristics of the wing under different inflow velocities during the transition phase. The research results indicate that the lift and drag of the wing increase first and then decrease with the increase of folding angle, especially at higher inflow velocities, where airflow separation is significantly intensified, resulting in a significant increase in drag. When the folding angle f=0°, i.e. no folding occurs, the propeller can accelerate the airflow velocity on the upper and lower surfaces of the wing, thereby increasing lift. However, as the folding angle increases, the presence of the propeller changes the direction of the airflow, resulting in a decrease in actual lift compared to without the propeller.