Investigation on performance enhancement of flap based on dual synthetic jets

When the aircraft is in the process of taking off, landing and flexible maneuvering, flow separation occurs above the flap and rudder which is caused by the large deflection angle. It reduces the performance of the flap and rudder, or even makes them ineffective. In order to solve this problem, a performance enhancement technology of flap based on array dual synthetic jets was proposed. Aiming at seamless flap, the influence of different dual synthetic jets driving parameters on the lift force and flap performance was investigated. The investigation results show that the dual synthetic jets can generate periodic vortex structures above the flap surface, which enhanced the momentum exchange between the low-velocity air in the boundary layer and the main flow. These vortex structures can also strengthen the ability of the boundary layer to resist the adverse pressure gradient. The array dual synthetic jets at the flap can effectively increase the lift force and enhance the flap performance. The flap performance enhancement is more effective when the dimensionless driving frequency is 3.89 and the momentum coefficient is 3.01 × 10^–3. The integrated model of the array dual synthetic jets actuator combined with the wing was designed and fabricated, and the flight test was carried out. The rolling angular velocity could achieve 15.69 (°)/s, which verifies the feasibility and effectiveness of performance enhancement of flap based on dual synthetic jets.