Title: Experimental investigation of the wake behind a rotating sphere,
Abstract: The wake behind a sphere, rotating about an axis aligned with the streamwise
direction, has been experimentally investigated in a low-velocity water tunnel
using LIF visualizations and PIV measurements. The measurements focused on the
evolution of the flow regimes that appear depending on two control parameters,
namely the Reynolds number $Re$ and the dimensionless rotation or swirl rate
$\Omega$, which is the ratio of the maximum azimuthal velocity of the body to
the free stream velocity. In the present investigation, we cover the range of
$Re$ smaller than 400 and $\Omega$ from 0 and 4. Different wakes regimes such
as an axisymmetric flow, a low helical state and a high helical mode are
represented in the ($Re$, $\Omega$) parameter plane.