Three-dimensionality and secondary vortex street in the wake of cylindrical bluff bodies

The aerodynamics of bluff bodies, such as cars or trucks, are largely dominated by vortex dynamics (regions of rotating flow). This thesis describes water channel experiments on spinning and stationary cylinders, which add to a better understanding of three-dimensional transitions and vortex interactions in incompressible bluff body wakes. The flows downstream of a slender cylinder of circular or elliptical cross-sectional shape and a flat plate are studied. New three-dimensional modes in the wake of a spinning cylinder and a new flow regime behind an elliptical cylinder are observed and explained for the first time.