(316s) Flow of Suspension past a Cylinder at Low Reynolds Number

We have measured the fluid velocity profile for free surface flow of suspensions past a cylinder at low Reynolds number. The measured velocity profile (with particle tracking velocimetry) is anisotropic even at particle concentration as low as 20 %. The anisotropy is more pronounced at higher concentration. The experiments were carried out at conditions where no significant migration of the particles is expected. It is argued that there is slip velocity of suspended particles at the surface of the cylinder. The observed anisotropy can be attributed to this phenomena.