A sphere is a prototypical bluff body and although studied for over a century, the wake of a sphere still poses many questions. Recently, we have been using state-of-the-art tomographic particle image velocimetry to measure for the first time the instantaneous three-dimensional flow structure in the wake of a sphere. In particular we found evidence for the generation of so-called induced vortices whose legs (IVL) and head (IVH) can be observed.
