Response Surface Method Application to High-Lift Configuration with Active Flow Control

The use of response surface method is presented and applied to the design of an active flow control for high-lift applications. The active flow control is used for suppression of the flow separation on the slotted flap. The position, orientation, and continuous excitation characteristics of the actuator are set as design variables for the maximization of cost functions in landing configuration. The actuators are placed in the cove of the airfoil. The active flow control is able to remove separation on the flap in this case completely. Subsequent verification of the efficiency of the optimum design, and possible energy saving, is done by an unsteady excitation. The unsteady excitation is simulated by periodic oscillatory pulse duty cycle. The influences of the excitation frequency and excitation time on the lift coefficient were examined. The frequency has almost no effect on C-L. On the other hand, it has been found that the excitation time can be reduced by about 97% within one excitation period of duty cycle, with only a small decreasing of C-L. It may decrease the energy requirements significantly.