Drifting of an Asymmetric Bent Rod in Two-Dimensional Shear Flow

At low Reynolds numbers, axisymmetric ellipsoidal particles immersed in a shear flow undergo periodic tumbling motions known as Jeffery orbits, with the orbit determined by the initial orientation. Understanding this motion is important for predicting overall dynamics of a suspension. While slender fibers may follow Jeffery orbits, many such particles in nature are neither straight nor rigid. Recent work exploring the dynamics of curved or elastic fibers have found Jeffery-like behavior along with chaotic orbits, decaying orbital constants, and cross-streamline drift. Most work focuses on particles with reflectional symmetry; we instead consider the behavior of a composite asymmetric slender body made of two straight rods in a 2-D shear flow to understand the effects of shape on the dynamics. We find that for certain geometries the particle does not rotate and undergoes persistent drift across streamlines. This drift is of a similar magnitude to that in the literature but arises from a different mechanism. Such geometry-driven cross-streamline motion may be important in giving rise to Taylor dispersion for this class of particles, thereby potentially enhancing mixing.