Computational Study on the Control of Self-sustained Shock Oscillation around a Supercritical Airfoil in Transonic Flow

Abstract

Transonic flow around supercritical airfoil involves shock induced oscillation at certain free stream Mach number and angle of attack due to the interaction of shock wave with airfoil boundary layer. This interaction consequences fluctuating lift and drag coefficient, aero acoustic noise and vibration, intense drag rise, high cycle fatigue failure (HCF), buffeting and so on. Moreover, the unsteady pressure fluctuations generated by the shock motions are highly undesirable from structural integrity and aircraft maneuverability point of view. The aerodynamic characteristics of the present problem have been solved by numerical computation. A commercial finite volume CFD package has been used for this computation. The computational domain has been discretized into a structured mesh by using a commercial preprocessing tool. The transonic flow around a supercritical airfoil is governed by the unsteady compressible Reynolds-averaged Navier-Stokes equation together with the energy equation. Two additional equations of k-ω SST turbulence model have been included to model the turbulence in the flow field. The results obtained from the numerical computation have been validated with the experimental results. Maintaining same flow parameters computational analysis has been done at free stream Mach number 0.77 and angle of attack from 2° to 7°. Mach contour, lift and drag coefficient, pressure coefficient and pressure history at different points over the airfoil has been captured and analyzed. To suppress the self-excited shock oscillation effectiveness of bump based passive control technique around the airfoil in transonic interval flows has been numerically analyzed and found its effectiveness.