Flow Structure behind Successively Dropping Spheres in Aqueous Surfactant Micellar Solution(Fluids Engineering)

Abstract

In the present study, flow structure behind a sphere falling through aqueous solutions of CTAB/NaSal are examined using a dye visualization and a PIV. Visualized dye patterns indicate that aqueous solutions of CTAB/NaSal forms multi layered structure behind a falling sphere. At relatively low salt concentrations, it is observed that the dye detaches from a sphere with its end moving upward where the velocity of fluid in the wake is in the opposite direction to the sphere sedimentation. On the other hand, at relatively high salt concentrations, these phenomena are not observed. At the moment of sudden acceleration of the sphere during sedimentation, the dye string behind the sphere contracts rapidly, accompanied by the rapid increase of upward velocity of flow behind the sphere inducing strong flow of the ambient fluid.