Influence of Turbulence Intensity on Aerodynamic Characteristics of an NACA 0012 at Low Reynolds Numbers

摘要

The objective of this study is to clarify the influence of turbulence intensity on the aerodynamic characteristics of an NACA 0012 airfoil at Reynolds number in the order of 10~4. Experiments were conducted by using a low-density testing capability of the Mars Wind Tunnel at Tohoku University. For Reynolds number below 50,000, aerodynamic force and pressure distribution on the model were measured using a force balance and pressure sensitive paint (PSP) for various turbulence intensities. Turbulence intensity in the wind tunnel was changed by using wire-mesh grids having different wire diameters. The results obtained in this study indicated that an increase of turbulence intensity had an effect to improve lift and drag characteristics of the airfoil. With an increasing turbulence intensity, the lift coefficient increased at low angles of attack and near the stall angle. The drag coefficient decreased in all conditions. Also, improvements of the stall angle and the maximum lift coefficient were observed. The characteristics of an NACA 0012 airfoil was dependent both on Reynolds number and turbulence intensity. The overall effects of increasing turbulence intensity were similar to those of increasing Reynolds number.