Abstract
The motion of a solid sphere sedimenting at its terminal velocity through worm-like micelle solutions is experimentally investigated. A rotational motion of a sphere is detected by tracking marker points on the surface of the sphere. Abrupt acceleration in sedimenting velocity of a sphere is found to be accompanied by its sudden rotation followed by sudden deceleration in sedimenting velocity and cessation of rotational motion. We suggest that the onset of this motion is caused by the partial detachment and adhesion of flow induced structured fluid on the interface of the sphere and unbalanced tensile forces lead to the rotational motions.
