Drag reduction on a transonic airfoil

Flow control for turbulent skin-friction drag reduction is applied to a transonic airfoil improve its aerodynamic performance. The study based on direct numerical simulations (with up 1.8 billion cells) of the compressible flow around supercritical airfoil, at Reynolds and Mach numbers $Re_\infty = 3 \times 10^{5}$ $M_\infty =0.7$ . Control via spanwise forcing over fraction suction side airfoil. Besides locally reducing friction, modifies shock wave significantly improves efficiency by increasing lift decreasing drag. Hence, can achieve required lower angle attack with Estimates aircraft level indicate that substantial savings are possible; when active, energy cost becomes negligible thanks small application area. We suggest should be considered not only as goal, but also tool global aerodynamics complex flows.