Design of High-Efficiency Jet Lift Enhancement for Flaps Under Propeller Slipstream Influence

Both propeller slipstream and flap jet flow can significantly increase the aircraft lift coefficient. To establish design principles for efficient lift enhancement via jet flow under the influence of slipstream, wind tunnel experiments are conducted on a wing with propeller slipstream and jet flow. Force measurements using a balance and flow field measurements using hot-wire anemometry are employed to investigate the effects of different jet flow distribution methods on lift enhancement. The results indicate that the coupling of slipstream and jet flow effects can significantly increase wing lift. The stronger the slipstream effect, the more pronounced the lift enhancement under the same momentum coefficient. At the same thrust coefficient, a higher momentum coefficient is required in the slipstream-affected region to suppress airflow separation. Under the same jet flow rate, increasing the momentum coefficient in the slipstream-affected region can significantly improve lift enhancement. At the thrust coefficient of 0.46 and the momentum coefficient of 0.1, the optimized jet flow distribution method achieved a 52.6% greater lift enhancement compared to the spanwise uniform jet flow distribution method.