Airfoil-Boundary Layer Subjected to a Two-Dimensional Asymmetrical Turbulent Wake

Abstract

The results of an experimental study of interaction between an incompressible two-dimensional asymmetrical turbulent wake produced by a symmetrical airfoil at incidence and a boundary layer formed on a similar airfoil immediately downstream are discussed. Extensive measurements of time-averaged quantities of the e ow and turbulence characteristics in the interaction region are performed. Particular attention is paid to analysis of the e ow structure with the downstream airfoil position being changed across the wake. In particular, a signie cant reduction in thelevel of turbulent velocity e uctuations hasbeen found in the boundary layer if the airfoil is located in the wake periphery. A similar effect also has been registered in the outer e ow region (outside the boundary layer) for the case when the wing is located in the central part of the wake. Although the interaction process has rather a complicated character, the distribution of the normalized mean velocity defect in the outer region of the interactinge owcanberoughlydescribedin theframeofwell-knowncorrelationsvalidforawakee owimmediately downstream of a transverse-positioned circular cylinder. A detailed analysis of the interacting e ow components (i.e., isolated turbulent wake and boundary layer ) is presented, and a possibility of their description in self-similar variables is shown.