Chirality-specific lift forces of helix under shear flows

Abstract

Chiral objects in a shear flow experience a chirality-specific lift force. Shear flows past helices in low Reynolds number regime are studied by a highly efficient iterative method, based on the analytical solution of a sphere in uniform flow. The chirality-specific lift forces in the vorticity direction experienced by helices are dominated by a set of helix geometry parameters: helix radius ([Formula: see text]), pitch length (b), number of turns and helix phase angle. Its analytical formula is firstly given. The chirality-specific forces are the physical reasons for the chiral separation of helices in shear flow. Our results are qualitatively in agreement with the simulation results and well supported by the latest experimental observations.