Stability of dense simple fluids subjected to large shear: Shear-induced ordering.

Abstract

The stability at finite wave numbers of a dense simple fluid subjected to a large shear is examined using generalized hydrodynamics and hard-sphere kinetic theory. For a fixed density below the equilibrium freezing density, for molecular-scale wave numbers, and for a critical shear rate, the fluid is found to become unstable with respect to density waves in the direction of the velocity gradient. For a given density the critical shear rates obtained are close to those found by Erpenbeck [Phys. Rev. Lett. 52, 1333 (1984)] in his nonequilibrium-molecular-dynamics simulations of shear-induced ordering.