|
Description:
|
A numerical 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 combined source and vortex panels . The source strengths are prescribed to have the same magnitude as the normal relative velocity on the surface due to the freestream and motion of the airfoil . The vertex 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 . Calculation results are presented for steady motion , impulsively started rectilinear motion , harmonic pitch oscillations , and constant pitching motions . Experimental data and analytical solutions are also presented for comparison . |