Abstract
Transient lift on a flat-plate airfoil in an incompressible uniform flow for a step increase in angle of attack is solved by applying Fourier transformation to a previously reported extended lift on an oscillating flat-plate airfoil with wake vortices assumed to move downstream at an arbitrary and constant velocity. The transient lift, which depends both on the position of the airfoil rotation axis and on the convection velocity of the wake vortices, includes a new term that is not reported in the classical theories. This term yields initial impulsive variations in lift. The relationship between the present solution and Wagner’s classical function is also clarified.
