Propeller-wing coupled aerodynamic design based on desired propeller slipstream

Considering the multi-propeller characteristics of DEP configuration, the lift-to-drag ratio of the wing is improved by optimizing the slipstream of the propeller, rather than changing the chord length and twist distribution along the span of the wing. First, a propeller design method is proposed to obtain the target induced velocity distribution, and then, a calculation model Prop−wing of propeller-wing integration is established based on the designed induced velocity distribution and panel method. Finally, an efficient optimization algorithm based on genetic algorithm (GA) and Kriging surrogate modeling is used to optimize the induced velocity distribution of the slipstream for higher lift-to-drag ratios. The optimization results show that when the thrust is constant, the larger the axial induced velocity close to the hub, the better the drag characteristics of the wing. When the chord length of propeller is not limited, the drag decreases by 30.48% and the lift-to-drag ratio increases by 51.93%. A 13.68% drag reduction and 18.80% lift-to-drag ratio improvement can be obtained.