The segregation of sheared binary fluids in the Bray-Humayun model

Abstract

The phase separation process which follows a sudden quench inside the coexistence region is considered for a binary fluid subjected to an applied shear flow. This issue is studied in the framework of the convection-diffusion equation based on a Ginzburg-Landau free energy functional in the approximation scheme introduced by Bray and Humayun [{\it Phys.Rev.Lett.} {\bf 68}, 1559, (1992)]. After an early stage where domains form and shear effects become effective the system enters a scaling regime where the typical domains sizes $L_\parallel $, $L_\perp$ along the flow and perpendicular to it grow as $t^{5/4}$ and $t^{1/4}$. The structure factor is characterized by the existence of four peaks, similarly to previous theoretical and experimental observations, and by exponential tails at large wavevectors.