Numerical experiment of flow characteristics of tandem arrangement two symmetrical airfoils

A numerical simulation was performed using a vortex method in order to investigate the fluid mechanical interferences of two tandem airfoils at variable angles of attack. Based on the shape of a vessel or a submarine, the mutual distance between the two airfoils (distance ratio) and the range of angle of attack were chosen. A symmetrical airfoil NACA0012 was used and the Reynolds number was Re = 3.8×105. The setting of distance ratio was L/c = 5.0, the attack angle of airfoils were varied as α = 0, 5, 10 and 15 degrees. As a result of calculations, when both airfoils were the same attack angles, the value of the lift coefficient of the 1st airfoil was larger than the value of the lift coefficient of the 2nd airfoil at all attack angles. It was found that a lift occurs also in one airfoil without an attack angle by mutual interference. And it was shown that the fluid force characteristic of each airfoil of two airfoils differs from the case of single airfoil.