Numerical simulation of separation control for high lift system using distributed zero-net mass flux jet

In order to improve takeoff and landing performance of large transport airplane, a typical three element airfoil is selected; we study the feasibility of distributed zero-net mass flux jet for improving the aerodynamic performance of the high lift systems. Flow mechanism of zero-net mass flux jet and distributed zero-net mass flux jet and the impact of their parameters are analyzed, including slot distribution, momentum coefficient and excitation frequency. Research results indicate that, no matter blowing or suction, zero-net mass flux jet can improve boundary layer energy and delay flow separation; it is better than one without flow control, but it cannot eliminate flow separation, while distributed zero-net mass flux jet can. Simulation results indicate that, when zero-net mass flux jet is working, the lift coefficient can increase by 7.1%, while distributed zero-net mass flux jet results in an increase by 20.3%; therefore distributed zero-net mass flux jet has better performance on flow control. Distributed zero-net mass flux jet is not only simple linear integration of every actuator, but also is beneficially influenced by every actuator. Four port distributed zero-net mass flux jet with momentum coefficient of 0.002, excitation frequency of 1 is best; it can eliminate flow separation on flap and improve lift coefficient significantly.