Abstarct: In this study the idea of huge humped flipper morphology is used to control the flow over airfoil, by implementing waves on airfoil and its effect on lift and drag coefficient and delay in stall by using numerical method is investigated. To achieve this goal, the flow around airfoil S809 is simulated by using Spalart–Allmaras turbulent model at Reynolds number of 6.5×〖10〗^5 and different angles of attack. In the current study, three different wavy airfoils are considered. For the first one, the leading edge and the trailing edge with a fixed wave amplitude of 1.5% of chord length in the span-wise direction with 5 different wave numbers is used. For the second one, in addition to the leading edge, 4 different waves are implemented on trailing edge and the span of the airfoil in the chord-wise direction. The third wavy airfoil is a mix of the first and second mentioned airfoils. By considering the obtained results the most optimized results after the post stall angle occur in first type of wavy airfoil, S10LT15C00 and second type of S10LT15C06. The surface pressure distribution and the structure of flow over wavy airfoil is very different with regarding to the standard model for the post stall angles. For the standard airfoil the flow was separated from airfoil and it encounters sever decrease in the lift coefficient and an increasing in drag coefficient which results in a stall. In wavy airfoil S809 in comparison with standard airfoil, the lift coefficient increases and then decrease with a smooth slope. Also the drag coefficient decreases which results in an increase in performance. Due to the result, the flow over the wavy airfoil leading edge at the post stall angle of attack remains attached to the body and the stall is delayed.