Thinning or thickening? Multiple rheological regimes in dense suspensions of soft particles Auteur(s): Kawasaki T., Ikeda A., Berthier L. (Article) Publié: Europhysics Letters (Epl), vol. 107 p.28009 (2014) Texte intégral en Openaccess : Ref HAL: hal-01053378_v1 Ref Arxiv: 1404.4778 DOI: 10.1209/0295-5075/107/28009 WoS: 000340779900036 Ref. & Cit.: NASA ADS Exporter : BibTex | endNote 39 Citations Résumé: The shear rheology of dense colloidal and granular suspensions is strongly nonlinear, as these materials exhibit shear-thinning and shear-thickening, depending on multiple physical parameters. We numerically study the rheology of a simple model of soft repulsive particles at large densities, and show that nonlinear flow curves reminiscent of experiments on real suspensions can be obtained. By using dimensional analysis and basic elements of kinetic theory, we rationalize these multiple rheological regimes and disentangle the relative impact of thermal fluctuations, glass and jamming transitions, inertia and particle softness on the flow curves. We characterize more specifically the shear-thickening regime and show that both particle softness and the emergence of a yield stress at the jamming transition compete with the inertial effects responsible for the observed thickening behaviour. This allows us to construct a dynamic state diagram, which can be used to analyze experiments. Commentaires: 6 pages, 3 figures |