Three-dimensional rotational dynamics of prolate particles in a circular tube

The 3D rotational dynamics of prolate particles in a low Re circular tube flow is experimentally analyzed by employing digital holographic microscopy. The 3D rotational motion of prolate particles is observed and compared with the existing theory on 3D particle dynamics. A particle tumbles with different orientations in a low Re tube flow. The rotational period of particles in a circular tube depends on their radial location. The rotational period of particles located at the non-equilibrium position inside the circular tube differs from that in the previous studies. The deviation from the theoretical results increases as the particle locates away from the equilibrium radial position of 0.5R. This experimental analysis provides unrevealed 3D rotational features of prolate particles and can help develop a new model for the rotational motion of ellipsoidal particles in a circular conduit.