Nonlinearity of the Aerodynamic Characteristics of NACA0012 Aerofoil at Low Reynolds Numbers

Aerodynamic characteristics of NACA0012 airfoil at low Reynolds numbers (Re=1.0×104∼1.0×105) are measured systematically to clarify nonlinearity of the aerofoil characteristics. The variation of the lift curve with the angle of attack is divided into 5 sub-regions; the gradient of the lift curve much depends on the incident angle. Negative values of the gradient of lift coefficient are observed at lower angles of attack in a Reynolds numbers range. The sub-regions are summarized in a diagram of angle of attack and Reynolds numbers. The coefficients of drag and moment around 0.25 chord length have also unique characteristics.