The efficiency analysis of gust alleviation based on active flow control

The feasibility and efficiency of gust load alleviation is presented in this paper based on active flow control (AFC) technique. Numerical simulations are conducted to investigate the beneficial effects on the aerodynamic characteristics of the NLR airfoil using the AFC technique and conventional control surface during the gust process. Based on unsteady Navier-Stokes equations, the grid-velocity method is introduced to simulate the gust influence, and an unsteady suction/blowing boundary condition is enforced over a user specified portion of the airfoil's surface to emulate the AFC actuator. Firstly, the efficiency of gust load alleviation with flap deflection is verified. Furthermore, with the introduction of kinds of AFC technique, it is demonstrated that significant and gradual aerodynamic alternations are obtainable in the gusty flow, and the influence of AFC parameters are also conducted. And the physical analysis of the influence on gust alleviation is proposed to provide some guide for practice. Our results have indicated that the AFC technique, as a new technology of gust load alleviation, with the appropriate AFC parameters design, can effectively affect and suppress the fluid disturbances caused by gust, which is equivalent to the conventional flap deflection.