Effect of Flow Deflector on the Aerodynamic Performance of the S809 Airfoil

Abstract Airfoil stalls at large angles of attack (AoAs), creating flow separation, which directly deteriorates the aerodynamic performance. Numerical simulations were utilized to study a new passive flow control technique for wind turbines. This flow control technique is named flow deflector (FD) and mounted above the leading-edge of the S809 airfoil. The aerodynamic characteristics of the airfoils at Re =1×10 6 were analyzed by varying the structural parameters of the FD. The findings indicate that the FD significantly enhances the aerodynamic characteristic of the airfoil at large AoAs. The stall angle is delayed by a maximum value of 6°. Appropriate structural parameters can enable the FD to perform more effectively. The FD with a width of 0.02c, a normal direction position of 0.12c, a chordwise direction position of 0, a deflection angle of 75° and a single flat plate is recommended.