The motion of axisymmetric dipolar particles in homogeneous shear flow

Abstract

The respective effects of an external field and departure of suspended particles from spherical shape on the rotary motion of axisymmetric dipolar particles placed in a homogeneous shear flow are studied. The analysis shows that, owing to cumulative effects, even a weak external field or a small deviation from spherical shape can significantly modify the resulting motion relative to that found in the corresponding classical problems of torque-free particles or dipolar spheres in homogeneous shear. Thus, unlike the latter problems, there are in the present problem cases when all particles approach a single limit cycle; in other cases multiple stable equilibria simultaneously coexist and the orientation space is appropriately divided into corresponding domains of attraction; in some situations possessing appropriate symmetry properties, particles may, depending upon their respective initial orientations, either move along a family of periodic orbits or else converge to a stable equilibrium orientation.