Flow separation control of simple flaps based on dual synthetic jets

This study investigates the flow separation control capability of an array of dual synthetic jets on a high-angle simple flap. Through numerical simulations. The aerodynamic control characteristics and mechanisms of the flow field around the airfoil were analyzed under various parameters, with a detailed examination of the control evolution of the separation vortex. The results indicate that as the dimensionless momentum coefficient C_μ increases, the control effectiveness of the dual synthetic jets for flow separation progressively improves. Optimal lift enhancement and drag reduction effects are achieved when the dimensionless driving frequency F⁺=3.088 and the momentum coefficient C_μ=0.028 99, resulting in the best overall control performance within the investigated cases. Additionally, the array of dual synthetic jets effectively controlled the evolution of the separation vortex on the high-angle simple flap by accelerating the airflow over the upper surface of the airfoil attracting high-speed airflow from the shear layer to reattach to the surface, and low-energy airflow drawing in from the shear layer to counteract the viscous dissipation in the separation region. This cyclic process transforms the development of large-scale spiral vortices into smaller-scale vortices, alleviating the adverse pressure gradient on the flap surface and reducing energy dissipation in the flap.