Control of Flow Past an Airfoil Section Using Rotating Cylinders

Abstract

The flow past a NACA 0024 airfoil with a leading edge rotating cylinder is simulated numerically using the ANSYS CFX software. To delay the boundary layer separation from the airfoil surface, different configurations for the airfoil and the cylinder were used. A leading edge rotating cylinder with some of its surface area exposed to the free stream velocity was positioned on the airfoil. The shear stress transport turbulence model was used for the analysis. The lift coefficient for the airfoil with the rotating cylinder was found to be considerably higher as compared to the original airfoil. The lift and pressure coefficients and the velocity profiles for this airfoil compared well with published experimental data. The detached eddy simulation turbulence model was used to analyze the flow field for the wake regions and vortices created from the flow separation. The results predicted by this model were accurate in terms of the airfoil drag coefficient and had lower computational costs that are usually associated with the standard large eddy simulation model. The flow over the same airfoil with an addition of a flap and a second rotating cylinder was also analyzed using the shear stress transport model. The use of rotating cylinders on the airfoil increased the lift coefficient and the stall angle by delaying the flow separation. For the case with a leading edge rotating cylinder, the effect of the momentum injection from the cylinder rotation increased the lift coefficient by 60% and the stall angle by approximately 80% as compared to the original airfoil. For the airfoil with two rotating cylinders the stall angle was increased by 90% with the use of rotating cylinders as a moving surface.