A new rate-independent tensorial model for suspensions of non-colloidal rigid particles in Newtonian fluids

Olivier Ozenda (1, 2) , Pierre Saramito (2) , Guillaume Chambon (1)

1 UR ETGR (ETNA) - Erosion torrentielle neige et avalanches
2 EDP - Equations aux Dérivées Partielles

We propose a new tensorial model to describe the rheology of non-colloidal suspensions of rigid particles. Qualitatively, this model proves capable of reproducing the main non-Newtonian trends exhibited by concentrated suspensions: anisotropic and fore-aft asymmetric microstructure in simple shear and transient relaxation of the microstructure towards its stationary state. The model includes only few constitutive parameters, with clear physical meaning, that can be identified from comparisons with experimental data. Hence, quantitative predictions of the complex transient evolution of apparent viscosity observed after shear reversals are reproduced for a large range of volume fractions. Comparisons with microstructural data shows that not only the depletion angle, but the pair distribution function, are well predicted. To our knowledge, it is the first time that a microstructure-based rheological model is successfully compared to such a wide experimental dataset.

Mots clés: fluid mechanics; partial differential equations; viscoplasticity; viscoelasticity; complex fluids

Domaines: Analyse numérique [math.NA]

Olivier Ozenda, Pierre Saramito, Guillaume Chambon. A new rate-independent tensorial model for suspensions of non-colloidal rigid particles in Newtonian fluids. Journal of Rheology, 2018, 62 (4), pp.889-903. ⟨10.1122/1.4995817⟩. ⟨hal-01528817v6⟩