| A numerical procedure for predicting boundary layer development on airfoils at moderate Reynolds numbers is presented. A 2-equation, integral boundary layer approximation is used to represent the development of the steady boundary layer along the airfoil surface. Both laminar and turbulent boundary layers can be modeled. Laminar-turbulent transition is predicted using an "en" method. The boundary layer prediction is similar to that developed by M. Drela and implemented in the XFOIL software. A set of nonlinear, integral boundary layer differential equations are discretized and coupled to a set of edge velocity equations from an inviscid potential flow solver. The nonlinear system is solved with a full Newton's method. Several discretizations and coupling techniques are tested. Results are presented for various design iterations and NACA profiles. |
