Numerical Investigation of Leading Edge Blowing and Optimization of the Slot Geometry for a Circulation Control Airfoil

Numerical simulations for the aerodynamic analysis of a two-dimensional circulation control airfoil at high Reynolds numbers have been carried out. Circulation control systems need a relatively high amount of power to provide the necessary pressurized air. Hence major design paramters as slot height and additional blowing at the nose have been varied to improve the efficiency of the circulation control airfoil. The results show that a significant increase of the efficiency is possible. Additional blowing at the nose protects the leading edge against stalling at lower Mach numbers to enable very high lift coefficients. By variation of the slot height for some configurations the required momentum coefficient of the air jet could be reduced by about 20% at slightly lower lift coefficients.