Parametrical study on separation-induced transition and vortex dynamics of a reversed pitching airfoil

The pitching airfoils, applied to the vertical axis turbines and propellers, are critical extract more energy from environment. At retreating side, when airfoil blunt leading edge becomes trailing edge, transition vortex dynamics quite different that at advancing side. goal of present work is investigate evolution over reversed airfoil, with main focus on parametrical effect, including mean angle amplitude, reduced frequency Reynolds number. results show flow structure complex compared forward due earlier separation near sharp edge. Then, firstly occurs within separated shear layer then reattaches, generation leading-edge vortex. Near second appears two sides, resulting in asymmetrical boundary as incidence increases continuously. This event totally shown by always moving unsteadiness mainly induced vortex, which greatly affected parameters. Besides, trajectory some specific vortices also depends working conditions significantly. It believed this can deepen understandings underlying physics airfoils.