Theodorsen
Theodorsen refers to Theodore Theodorsen, an aerodynamics researcher whose work in the 1930s led to a foundational concept in unsteady aerodynamics. He is best known for introducing the Theodorsen function, a complex transfer function that describes how an oscillating, thin airfoil in incompressible, inviscid flow responds to harmonic motions. Theodorsen’s theory provides a linear, frequency-domain relationship between the airfoil’s motion (such as plunge and pitch) and the resulting aerodynamic loads.
Theodorsen function and definition
The Theodorsen function, C(k), relates unsteady lift and moment to the airfoil’s motion through a reduced frequency,
Theodorsen’s theory provides a practical framework for calculating unsteady aerodynamic forces on oscillating airfoils, useful in