From stress-induced fluidization processes to Herschel-Bulkley behaviour in simple yield stress fluids

By T. Divoux, C. Barentin, S. Manneville. 2010

150 citations recorded by the source corpus.

Stress-induced fluidization of a simple yield stress fluid, namely a carbopol microgel, is addressed through extensive rheological measurements coupled to simultaneous temporally and spatially resolved velocimetry. These combined measurements allow us to rule out any bulk fracture-like scenario during the fluidization process such as that suggested in [Caton et al., Rheol Acta, 2008, 47, 601–607]. On the contrary, we observe that the transient regime from solid-like to liquid-like behaviour under a constant shear stress σ successively involves creep deformation, total wall slip, and shear banding before a homogeneous steady state is reached. Interestingly, the total duration τf of this fluidization process scales as τf ∝ 1/(σ − σc)β, where σc stands for the yield stress of the microgel, and β is an exponent which only depends on the microgel properties and not on the gap width or on the boundary conditions. Together with recent experiments under imposed shear rate [Divoux et al., Phys. Rev. Lett., 2010, 104, 208301], this scaling law suggests a route to rationalize the phenomenological Herschel-Bulkley (HB) power-law classically used to describe the steady-state rheology of simple yield stress fluids. In particular, we show that the steady-state HB exponent appears as the ratio of the two fluidization exponents extracted separately from the transient fluidization processes respectively under controlled shear rate and under controlled shear stress.

Subfields: Computational Mechanics, Fluid Flow and Transfer Processes, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/826ff32b0a3717c520e4a36767754eaab4924be1

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In Computational Mechanics

In Fluid Flow and Transfer Processes

In Materials Chemistry

Citations in the corpus

Yielding to Stress: Recent Developments in Viscoplastic Fluid Mechanics (2014, methodology): “F or p er so na l u se o nl y. Static yield stress (τy,s ): the stress above which unyielded fluid begins to flow Dynamic yield stress (τy,d ): the stress below which yielded fluid stops flowing and an apparent viscosity that continually increases with time (Caton & Baravian 2008, Coussot et al. 200”
Deformation and flow of amorphous solids: Insights from elastoplastic models (2017, methodology): “That being said, the elastic moduli are usually only weakly affected by the preparation route, i.e., the cooling rate (Ashwin et al., 2013) and the waiting time (Divoux et al., 2011b), while other key features of the transient response to the applied shear are often found to depend on it.”
Rheological Characterization of Carbopol® Dispersions in Water and in Water/Glycerol Solutions (2019, background): “The same behavior was later reported by [79] for shear-stress controlled experiments.”