Optimization of the double-slot blown airfoil with jet at the leading and trailing edges of the flap

An active lift augmentation technique combining trailing edge blowing and blown flap is explored in this study. A double-slot blown flap airfoil is designed based on NACA23015. By optimizing the configuration parameters via the neural network surrogate model and particle swarm optimization algorithm, the lift coefficient at the 8° angle of attack reaches ∼5.14, which is approximately a 24% increasement relative to the baseline single-slot blown flap airfoil. In the configuration optimization, a longer flap facilitates lower pressure on the upper airfoil surface. Additionally, the aerodynamic flap effect caused by the double-slot jet flow intensifies the lift peaks and the pressure decreases over the airfoil. Ultimately, redistributing the jet momentum to the two slots achieves a highly efficient blown flap airfoil design.