Motion of Magnetic Spheres inside Cylindrical Tubes filled with Newtonian and Viscoelastic Fluids

The paper is dedicated to the experimental study of the motion of magnetized spheres in tubes filled with pure viscous and viscoelastic fluids. The main goal of the study is to investigate the spheres motion with variable velocities in confined geometries. Due to the influence of the attractive magnetic force the spheres are accelerated, therefore a non-stationary fluid flow is generated in the tubes. The experiments put in evidence the fluctuation frequency and the rotational speed of the sphere during its displacement within the tube. The influence of the fluids rheology on the spheres motion is also determined.