The Effect of the Turbine Airfoil Shape on its Aerodynamic Damping

Designing the low pressure stages of large gas turbines

requires extraordinary attention to account for aeroelastic

phenomena and its mitigations. A very hazardous

phenomenon is fl utter, a self-excited form of vibration,

which is caused by fl uid energy transferred into the blade

structure. To mitigate fl utter the designer can chose between

aerodynamic and mechanical measures. The present work

focus on the impact of the blade shape to modify the exciting

unsteady pressure fi elds leading to fl utter. Analytical as well

as numerical approaches are presented, which examine the

link between steady aerodynamics and the vibration induced

unsteady pressure. The results of these studies are used

to derived guide lines for the design of high-performance

airfoils with a reduced fl utter excitation and discussed in the

last chapter.