TABLE OF CONTENTS The trailing edge flap may be moved according to the instantaneous aerofoil state to attempt to reduce the structural deformation. Hence, active control has been implemented within the aeroelastic solver, in order to investigate active means of transonic flutter suppression via control surface (flap) and motion-aeroservoelasticity (closed loop calculations). A simple control law is used which relates the required flap deflection angle, ? c, to the motion of the main aerofoil surface (plunge and pitch degrees of freedom). Hence, ? c is evaluated according to the following equation
| (22) |  |
where the G s are the gains of the system.
The flap is moved according to the demanded deflection angle ? c. However, instead of moving the flap by ? c degrees within a certain amount of time (according to the flap deflection rate), the required angle is converted into equivalent control hinge moment (CHM) which is blended into the open loop aeroelastic equations as the external moment acting on the hinge axis, hence only affecting the ? degree of freedom. There are two hinge moments on the right hand side of the aeroservoelastic equation, the aerodynamic hinge moment (AHM) and the CHM as shown by equation (23)
| (23) |  |
This is because it is impossible to guarantee that the flap will move from ? to ? + ? c within a certain amount of time. By converting the required angle to the equivalent CHM the flap dynamics are accounted for.
