Numerical investigation of low speed performance of transonic coflow jet supercritical airfoil

This paper studies the low-speed performance of coflow jet (CFJ) supercritical airfoils based on three baseline supercritical airfoil of NASA SC(2)-1010, RAE-2822, and NASA SC(2)-0714. The simulations employ the intensely validated in-house CFD solver, FASIP, using Reynolds Averaged Navier-Stokes(RANS) equations with one-equation Spalart- Allmaras turbulence model. Numerical studies are carried out to investigate the effects of slots location and size, airfoil thickness, and jet intensity on the low speed performance of the airfoil. It is found that for the CFJ supercritical airfoils, very high maximum lift coefficient is obtained while improving the aerodynamic efficiency at cruise at low angle of attack(AoA). This study indicates that the CFJ-NASA-SC(2)-0714 supercritical airfoil is able to achieve super-lift coefficient of 9.1 at Mach 0.1, attributed to its large leading edge radius and airfoil thickness. Whereas the CFJ-RAE-2822 and CFJ-NASA SC(2)-1010 airfoils achieve lower maximum lift coefficient of 5.4 and 5.9 respectively. The overall low speed performance of supercritical CFJ airfoils is significantly superior to conventional super-critical airfoils. The results are very encouraging to achieve high lift coefficient for takeoff/landing without using the conventional flap systems.