ABSTRACT

Self-excited shock induced oscillation (SIO) around an airfoil is observed in transonic flows at certain conditions of free stream Mach number and angle of attack. At these conditions, the interaction of unsteady shock wave with airfoil boundary layer becomes complex and causes several detrimental effects such as the fluctuating lift and drag coefficients, aeroacoustic noise and vibration, high cycle fatigue failure (HCF), buffeting and so on. In the present study, Reynolds Averaged Navier-Stokes equations have been used to predict the aerodynamics behaviour over a NASA SC(2) 0714 supercritical airfoil in transonic flow conditions. To suppress the unsteady aerodynamic behaviour, a shock control bump is introduced at the mean shock position. Computations have been performed at free stream Mach number of 0.77 while the angle of attack was varied from 2° to 7°. The results obtained from the numerical computation have been validated with the experimental results. Mach contour, lift and drag coefficient, and pressure history over the airfoil surface have been analyzed for the cases of baseline airfoil and airfoil with bump. It is found that, the bump can control the unsteady SIO in the flow field.