Numerical Investigation on the Reynolds Number Effects of Supercritical Airfoil

Supercritical airfoil has been widely applied to large aircrafts for sake of high aerodynamic efficiency. The aerodynamic characteristics of supercritical airfoil are rather sensitive to Reynolds number. Therefore, Reynolds number has great effects on the economy, comfort and even safety of large aircrafts. Flows over a typical supercritical airfoil XY are numerically investigated for different Reynolds numbers in this paper; the two-dimensional Navier-Stokes equations are solved with structure grids by utilizing the Spalart-Allmaras (S-A) turbulence model. Computational results of RAE2822 airfoil compare well with wind tunnel results. The computation Reynolds numbers of XY airfoil vary from 2.0×106 to 50×106 per airfoil chord while mach numbers equal 0.74 and 0.8. It is shown that the upper surface pressure distribution including the location and intensity of shock wave and trailing-edge pressure coefficient, changed apparently with variable Reynolds numbers, when shock-induced trailing-edge separation exists. Results implied that Reynolds number effects should be considered while designing and optimizing large aircrafts applied supercritical airfoil.