Effective temperature for sheared suspensions: A route towards closures for migration in bidisperse suspension

By extending the concept of an effective temperature, earlier introduced for sheared monodisperse suspensions, we propose a continuum theory for sheared bidisperse suspensions. We show the theory for sheared suspensions can be constructed from the theory for Brownian suspensions by replacing the temperature with the effective temperature. Furthermore, we explore the validity of closure relations based on mean field/free volume theory, by comparison with experimental data obtained for Brownian bidisperse suspensions. In a recent paper, we have shown that the new theory, combined with the discussed closure relations, is indeed a predictive theory.

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► An effective temperature, linear in the shear stress, explains migration in sheared suspensions.
► Non-equilibrium osmotic pressure equals effective temperature times compressibility factor.
► All closures in the theory can be formulated in terms of free volume.
► Scaling of effective temperature with shear rate depends on the particular contact force.