Effects of the Cylinder Wake in a Freestream on Statistical Properties of a Turbulent Boundary Layer

Effects of the cylinder wake in a freestream on statistical properties of a turbulent boundary layer over a flat plate are investigated by means of wind tunnel experiments. The cylinder is set horizontally over the flat plate and the interactions between its wake and the zero-pressure-gradient turbulent boundary layer are investigated. Instantaneous velocity is measured by using hot wire anemometry. The bursting events are detected by the variable interval time average (VITA) technique. The results show that the time-averaged mean velocity in the inner layer with the cylinder wake coincides with that without the cylinder wake. However, turbulence intensities normalized by the inner parameters are suppressed by the cylinder wake. It is found that the peak value of the velocity fluctuation during the sweep phase in the bursting event is increased by the cylinder wake.