Abstarct: Development of a new generation of flying objects with more maneuverability and pitching capability at higher angles of attack (AOA) needs effective systems to control unsteady phenomena on their body. By growing interest in UAVs (Unmanned Aerial Vehicle) for military, probe into places where large flying objects are not capable of, and among other applications, demands the study of this field and improvement of the aerodynamic performance of these flying objects. Since the unsteady effects become stronger as the flying object size decreases, flow control over the surface of them become a necessity, which is one of the methods to increase the aerodynamic performance. The design and optimization of aerodynamic bodies are complex and astringent tasks that entails expensive experiments and plenty amount of time. These difficulties emphasize the important role of numerical simulation to reduce these experimental consequences. To predict the complex flow conditions, it is important to use suitable numerical techniques which have both acceptable convergence speed and accuracy. The numerical code uses the well-known Jameson's cell-centered finite volume numerical method accompanied by a progressive power-law preconditioning approach to suppress the stiffness of the governing equations. To achieve the steady state solution, the equations are integrated in time using an explicit four-stage Runge-Kutta scheme with local time step. For unsteady problems, a dual-time implicit algorithm is applied to obtain time-accurate solutions. Many numerical simulations are performed over airfoils, including the simulation of laminar/turbulent flows at 800<Re<2×10^6 and comparison of different preconditioning techniques and effect of suction-blowing control parameters, such as slot location (L_j), suction/blowing amplitudes (A_j), and suction/blowing angle (θ_j). Also an acceleration technique is introduced for and its accuracy is examined. The results show that the presented algorithm is capable of simulating different flow regimes from laminar to turbulent flows with/without active flow control. The obtained results illustrate that in the case of active flow control over airfoil, implementation of suction has more ipmprovement on the performance of the airfoil. Also no significant difference is obsereved between suction with 30 and 90 angles. Furthermore, blowing with the angle of 30 near the trailing edge has a better performance and also is more sensitive to the angle of blowing. Also it should be mentioned that blowing with the angle of 30 excel blowing with the angle of 90 degrees in improving the ratio of mean lift coefficient to mean drag coefficient (in some cases these improvement by assuming the same L_j and A_j is about 40 percent).