基于前缘合成双射流的飞翼布局纵向气动控制特性研究

This paper proposes a longitudinal aerodynamic control strategy for flying-wing aircraft utilizing dual synthetic jets to compromise the stealth performance and aerodynamic maneuverability. The performance of this method for a small-swept-angle flying wing at large attack-of-angle (AOA) is examined by investigating the interaction between leading-edge dual synthetic jets and flow fields at different AOAs. Results show that an array of dual synthetic jets at the leading edge can effectively increase lift, reduce drag, and increase the lift-to-drag ratio at large angle of attack. The nonlinearly varying pitch moment indicates that the roll attitude control at high AOAs can be realized. Dual synthetic jets induce periodically evolving vortices at the leading edge, strengthening the momentum mixing across the wall-normal direction and enhancing the capability to resist reverse pressure gradient. Depending on AOA, dual synthetic jets have varied performance. At the AOAs of 8−10 degrees, they can completely suppress the leading-edge separation, while at the AOA of 10 degrees, a small separation area around the trailing edge leads to a slight decrease of lift. At the AOA of 12 degrees, the separation line moves to the middle section of the wing. At the AOA of 14−16 degrees, they can only effectively suppress the flow separation around the spanwise front of the separation zone, but they can still improve the lift efficiency by intensifying the energy in the separation zone. At the AOA of 18 degrees, the flow over the suction surface is almost completely separated. Nevertheless, the suction at the leading edge increases so that a relatively high lift-to-drag ratio remains. Compared with traditional synthetic jets, dual synthetic jets can significantly improve aerodynamic performance, manifesting their great potential.