English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Complex fluids either natural or encountered in numerous industrial processes are often composed of several phases constituting emulsions, suspensions, foams or other colloidal dispersions. Many of these complex fluids may be described in a general manner as “soft-jammed systems” which have the ability to undergo a solid-liquid transition when submitted to a sufficient stress. The description of this transition from a solid state to a flowing situation is essential to understand for example the dynamic of flow stoppage or restart of natural processes (snow avalanches, ground sliding, etc.) or of industrial processes (self placement concrete, glues, cosmetic formulations, mud circulation, flow assurance, etc.). In this study, we have interest in the link between the microstructure of a complex fluid and its macroscopic rheological behavior, especially regarding the solid liquid transition characteristic of these systems. By coupling conventional rheometry giving macroscopic properties, and IRM velocimetry giving access to local properties, we can identify the structural origin of the major rheological properties as the yield stress, the aging at rest and the viscosity bifurcation in the liquid regime. We show that the progressive stoppage of the material, induced by the growing of aggregates under a critical stress explains some peculiar characteristics of the flow curves. We show then how the transient and stationary behavior of the fluid may be described by a unique thixotropic model involving a structural time and shear dependant parameter. A practical application of this model is proposed, showing how the parameters of the model may be deduced from simple experiments, and how the model may be used to predict restart conditions after rest for a fluid flowing in a pipe. This work allows to propose elements of microscopic modeling of the thixotropy of these systems in relation with their structure, and show the applicability of this modeling work to practical situations.

Modeling Aging and Yielding of Complex Fluids: Application to an Industrial Material