Fluid Flow Control Over An Airfoil

Abstract

High lift devices have become increasingly significant for airplanes and wind turbines because they prolong flow separation and improve fuel efficiency. However, even at a greater attack angle, fluid flow separation is likely to occur, leading to a loss of lift. Therefore, vortex generators are used to boost the lift even more. An increase in fuel efficiency can be achieved by simplifying complicated high lift systems. A simplified high lift system combined with flow separation control may be able to satisfy today’s high lift performance needs. In the present study, the use of NACA0012 and NREL S809 profiles is numerically investigated for flow separation control. The computational fluid dynamics approach employed in this investigation makes use of the Reynolds averaged Navier–Stokes (RANS) equations with Spalart–Allmaras model using ANSYS Fluent software. The results of the numerical analysis are validated with the experimental values available in the literature. The flow velocity and angle of attack are varied and subsequent CFD results of both the profiles are analyzed. The varying effect of velocity and angle of attack on the flow separation point on the airfoil profile is observed and corresponding Lift and Drag coefficients are evaluated. The optimum conditions for fluid flow are also determined. The numerical analysis results suggest that for maximum L/D ratio, the desired flow velocity is 12 m/s and the angle of attack is 10° for the NREL S809 profile.