Lift enhancement characteristics of distributed propulsion wing with propulsion-aerodynamic coupling

To reconcile the high-lift demands of short takeoff and landing (STOL) with the requirement for efficient cruise in unmanned aerial vehicles (UAVs), this paper presents a novel distributed propulsion wing lift enhancement configuration (DPWLEC) that capitalizes on aerodynamic-propulsive coupling. Based on the technical background of a specific distributed electric propulsion (DEP) STOL UAV, numerical simulations for multiple flight conditions, including STOL and cruise, are conducted. The study analyzes the aerodynamic-propulsion coupling characteristics and the evolution of the flow field structure for this configuration, revealing the influence of the propulsor number on the lift and drag characteristics. The research results indicate that during the STOL phase, the aerodynamic-propulsion coupling effect can be utilized to achieve optimal lift enhancement and drag reduction. A high lift coefficient of 2.68 is obtained simultaneously with a lift-to-drag ratio of 14.11. As the propulsor number increases from 6 to 18, the total lift increases by more than 60%. The total drag reaches its minimum value with a configuration of 12 propulsors, which represents the optimal DEP distribution for achieving the best combined lift-enhancement and drag-reduction effect. On the other hand, during the cruise phase, increasing the propulsor number effectively improves the overall lift-to-drag characteristics. After the propulsor number is increased to 18, the lift-to-drag ratio reaches up to a maximum value. These findings can provide theoretical support for the design of a new-generation of high-efficiency, high-maneuverability STOL aircraft.