Effect of control surface on aeroelastic characteristics of transonic airfoil

Based on the aerodynamic identification technique in which the unsteady CFD is used, the unsteady aerodynamic reduced order models (ROM) are constructed. Coupled with the structural equations, the models for transonic aeroelasticity in state-space are got. A Mach number flutter trend of a typical airfoil section with a control surface is analyzed and the results obtained agree well with those with CFD/CSD direct coupling method. Then the effects of the structural parameters (natural frequency and the flap static unbalance) of the control surface on the transonic flutter system are studied. Some traditional structural design rules are found to be unfavorable for transonic flutter problem. For transonic flutter problem, the flap pitch mode always becomes a leading mode of aeroelastic system. The traditional technology of mass static unbalance maybe reduces the stability of transonic aeroelasticity.