Numerical simulation on the effects of rotating cylinder on an airfoil

Moving surface boundary layer control technique appears quite promising for enhancing the airfoils aerodynamics prominently with little energy input. Numerical simulations are conducted on the NACA0015 airfoil with rotating cylinders. The ratio of cylinder surface speed to the freestream speed as well as the gap between the cylinder and the fixed section are analyzed. The results show that the high speed leading-edge rotating cylinder is effective on delaying the flow separation on the upper surface of the airfoil and retarding the boundary-layer development. The proper rotating speed ratio for the cylinder is around 4 and the appropriate gap distance is about 2.5mm to 1.5mm. Moreover, results suggest that, integrated with the high speed leading-edge and trailing-edge rotating cylinders, the aerodynamic performances of the symmetrical airfoil with simple flap can be comparative to those careful designed multi-element airfoils.