Abstract: Combining the characteristics of suction-transition control and micro-blowing turbulence-drag-reduction technology, a novel suction-blowingcontrol technique is put forward to reduce airfoil drag. By using the computational fluid dynamics (CFD) code of Fluent, the Wilcox transition mode is modified by a user-defined function (UDF) and incorporated into the CFD code. Based on the above modifications, the effect of suctionblowing control on the airfoil drag performance is numerically studied. The results show that when the suction flow rate are in a certain range, suction and suction-blowing control can both reduce the total drag of an airfoil. At the same Reynolds number, the leadingedge suction without blowing reduces the total drag below the airfoil by up to 3%, while the suction-blowing control results in a drag reduction by up to 16%. Therefore, the suction-blowing control technique is an effective way for drag reduction control.

Key words: airfoils, laminar flow, transition, turbulence-drag reduction, suction-blowing control