Unsteady aerodynamic performance and mechanism of blunt trailing-edge airfoils

The aerodynamic performance of blunt trailing-edge airfoils is always affected by the shedding of wake; therefore, the unsteady aerodynamic performance of airfoil DU 91-W2-250 6 which is from DU 91-W2-250 by symmetrically adding thickness on both sides of the airfoil was numerically investigated with fine grids in this paper. The performance is periodic at every angle of attack, and the specific characteristics such as the amplitude and period is induced by the size and location of shedding vortex and by the width of the wake. The lift coefficients reaches the peak when the anticlockwise vortex just sheds from the trailing edge, while it reaches the valley when the clockwise vortex just sheds.