Effect of angle of attack on flutter characteristics of a control surface with free play nonlinearity

Limit cycle flutter of a 3D supersonic control surface with preload free play is studied. CFD (computational fluid dynamics) based local piston theory is use to compute unsteady aerodynamic loads, and equivalent linearization method is use to analysis the limit cycle flutter of the control surface. The effects of angle of attack and free play on the characteristic of the limit cycle flutter are studied. The results show that aerodynamic preloads and reduction of the free play can improve the stability of the aeroelastic system. For this supersonic control surface, if the linear flutter speed and free play of the rudder satisfies the national military standard, acute flutter won't appeal in the flight state, only small amplitude limit cycle oscillation will appeal at 0 angle attack flight.