The near-wake structure of a cantilevered cylinder in a cross-flow

Flow visualization experiments on a circular cantilevered cylinder in homogeneous cross-flow have been performed in order to study the effect of the three-dimensional flow around the free end on the flow around the shaft. Special attention was given to the region of the near-wake since it is most sensitive to three-dimensional disturbances - in particular those by the three-dimensional flow over the top. The structural analysis of mean regular motions in the near-wake flow yielded to a scheme of superimposed vortex systems: in the shaft region periodic vortex shedding is dominant. The top region is governed by a stationary vortex system consisting of four conical vortex sheets. Two secondary flows due to these vortices are observed: the stationary central downwash and the stationary secondary flow along the separation line directed towards the cylinders' free end.