Turbulent Boundary Layer-Wake Interaction

The interaction of a two-dimensional, incompressible, turbulent boundary layer on a flat plate with a plane wake of a circular cylinder was investigated experimentally and theoretically. The cylinder was positioned at various distances above the plate, with the axis normal to the free-stream direction and parallel to the surface of the plate. The time-averaged velocity components, the Reynolds stresses, the wall-pressure distribution and the wall shear stresses were measured downstream from the cylinder in the wake and in the boundary layer. Mean and fluctuating velocities were measured with hot-wire probes, conventional data reduction was used. It could be shown that the wake retains its self-preserving characteristics in the outer part and approximately in the inner layer as well. The profiles of the Reynolds stresses in the interacting part of the flow were used to deduce a mixing-length closure assumption, which was incorporated in a numerical finite-difference simulation of the relaxing boundary layer.