Inviscid Flowfield of an Unsteady Airfoil

Simple formulas have been developed from thin airfoil theory to describe the detailed inviscid, incompressible flowfield of an unsteady airfoil with thickness and camber. The solutions allow the various physical aspects of the problem and the parameters of the unsteady motion to be identified easily. The results agree well with numerical calculations and pressure measurements. The unsteady phase lag and attenuation of the inviscid pressure gradients near the leading edge explain the dynamic delay in laminar boundary-layer separation on oscillating airfoils, but not the characteristics of dynamic stall.