Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation P. Coussot, Q. D. Nguyen, H. T. Huynh, Bonn; Viscosity bifurcation in thixotropic, yielding fluids. J. Rheol. 1 May 2002; 46 (3): 573–589. https://doi.org/10.1122/1.1459447 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Dropdown...

We show that, above a critical stress, typical yield stress fluids (gels and clay suspensions) soft glassy materials (colloidal glasses) start flowing abruptly subsequently accelerate, leading to avalanches that are remarkably similar those of granular materials. Rheometrical tests reveal this is associated with bifurcation in rheological behavior: for small stresses, the viscosity increases time; material eventually stops flowing. For slightly larger stresses decreases continuously flow...

Magnetic-resonance-imaging rheometrical experiments show that concentrated suspensions or emulsions cannot flow steadily at a uniform rate smaller than critical value (gamma(c)). As result, "liquid" region (sheared rapidly, i.e., larger gamma(c)) and "solid" (static) coexist. The behavior of the fluid in liquid follows simple power-law model, while extent solid increases with degree jamming material.

We carried out systematic creep tests after different times of rest and over sufficiently long with pasty materials various internal structures in a Couette geometry. From an analysis the data taking into account inertia system heterogeneous distribution stress, we show that: (i) for stress below yield these remain solid but undergo residual, irreversible deformations time which exhibit some trends typical aging glassy systems; (ii) as result thixotropy (or aging) regime elastic modulus...

We study experimentally the behavior of isotropic suspensions noncolloidal particles in yield stress fluids. This problem has been poorly studied literature, and only on specific materials. In this paper, we manage to develop procedures materials that allow us focus purely mechanical contribution fluid behavior, independently physicochemical properties allows relate macroscopic these particle volume fraction, provide results applicable any fluid. find elastic modulus-concentration...

The transition from frictional to lubricated flows of a dense suspension non-Brownian particles is studied. pertinent parameter characterizing this the Leighton number Le=eta(s)gamma / sigma, ratio lubrication forces. Le defines critical shear rate below which no steady flow without localization exists. In regime localized. not simply viscous: normal stresses remains constant and velocity profile has universal form in both regimes. Finally, discrepancy between local global measurements...

To predict mudflow dynamics a numerical model based on shallow-water equations is developed. Previous work has shown that behavior can be well represented by Herschel-Bulkley model. In laminar regime, generally observed in practice, wall friction force expression been theoretically deduced for steady uniform flows. For unsteady flows the assumed to equal resistance of flow with same depth and mean velocity. The parameters, directly from model, are determined independently rheological...

We show that the rheological properties of dry granular materials, as well foams and emulsions, are similar to typical thixotropic fluids: under a sufficiently strong shear viscosity decreases in time, leading hysteresis an up-and-down stress ramp. This leads bifurcation around critical stress: for smaller stresses, increases time material eventually stops flowing, whereas slightly larger stresses continuously with flow accelerates. These results all jammed systems exhibit mechanical...

We study the Saffman-Taylor or viscous fingering instability in yield stress fluids. The theory for fluids shows that dispersion equation of is similar to Newtonian fluids; however, capillary number governing now contains stress. Experiments using gels and foams reveal very branched fingers gel. results are excellent agreement with gel, with, addition, a crossover from dominated behavior. different due existence wall slip.

Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation V. Bertola, F. Bertrand, H. Tabuteau, D. Bonn, P. Coussot; Wall slip yielding in pasty materials. J. Rheol. 1 September 2003; 47 (5): 1211–1226. https://doi.org/10.1122/1.1595098 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search...

Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Hervé Tabuteau, Philippe Coussot, John R. de Bruyn; Drag force on a sphere in steady motion through yield-stress fluid. J. Rheol. 1 January 2007; 51 (1): 125–137. https://doi.org/10.1122/1.2401614 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex...

Clay-water suspensions are shear-thinning yield stress fluids whose apparent viscosity increases with solid fraction. It is shown experimentally that, in a wide fraction range, their behavior similar and goes through transition from non-Newtonian to Newtonian when nondimensional shear rate increases.

Flows of dense emulsions show many complex features among which long range nonlocal effects pose a problem for macroscopic characterization. In order to get around this problem, we study the flows several emulsions, with droplet size ranging from $0.3\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}40\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$, in wide-gap Couette geometry. We couple rheometric experiments and local velocity measurements through magnetic resonance...