VISCOUS-INVISCID INTERACTION METHOD FOR STEADY TRANSONIC FLOW

A numerical method for steady load determination on airfoils in a transonic flow with the occurrence of a shock wave is demonstrated. The method implements the Euler equations for the inviscid region and integral boundary layer equations for the viscous region near an airfoil. The viscous-inviscid interaction is implemented through transpiration velocity. The Euler solution is calculated by applying the Van Leer flux-vector splitting on a body-fitted C-grid. The boundary layer model is calculated applying Drela's model of integral boundary layer equations for a laminar and a turbulent flow. The transition is predicted by the e(n) method. The viscous-inviscid interaction method is carried out in a direct mode. The method gave comparable results with the calculated RANS results and experimental data, while time and computational costs were slightly higher than for the pure Euler calculations. The method predicted the position of a shock wave slightly shifted toward the trailing edge of airfoil with respect to the position obtained by experiment, but in front of the RANS and Euler results.