A numerical method for the calculation of unsteady lifting potential flow problems

A potential flow model for two-dimensional airfoils in unsteady motion with boundary layer separation is described. The airfoil and wake surfaces are represented by a finite set of uniform strength doublet panels. The doublet strengths on the airfoil surface are determined by applying a kinematic surface tangency condition to a Green's function representation of the potential field, while simultaneously enforcing the Kutta condition. Wake shedding is governed by a dynamic free surface condition and the characteristics of the flow near any boundary layer separation points. Wake deformation is predicted by applying a geometric free surface condition.