Frequency response of lift coefficient according Theodorsen’s theory.
The output is a 3 elements array containing the CL frequency response w.r.t. to pitch, plunge and flap motion, respectively. Sign conventions are as follows:
plunge: positive when moving upward
x_ea_perc: position of axis of rotation in percentage of chord (measured from LE)
x_fc_perc: position of flap axis of rotation in percentage of chord (measured from LE)
this function uses different input/output w.r.t. theo_lift