Giant superhydrophobic slip of shear-thinning liquids

Fuente: arXiv
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Main Authors: Schnitzer, Ory, Ray, Prasun K.
Format: Preprint
Published: 2024
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author Schnitzer, Ory
Ray, Prasun K.
author_facet Schnitzer, Ory
Ray, Prasun K.
contents We theoretically illustrate how complex fluids flowing over superhydrophobic surfaces may exhibit giant flow enhancements in the double limit of small solid fractions ($ε\ll1$) and strong shear thinning ($β\ll1$, $β$ being the ratio of the viscosity at infinite shear rate to that at zero shear rate). Considering a Carreau liquid within the canonical scenario of longitudinal shear-driven flow over a grooved superhydrophobic surface, we show that, as $β$ is decreased, the scaling of the effective slip length at small solid fractions is enhanced from the logarithmic scaling $\ln(1/ε)$ for Newtonian fluids to the algebraic scaling $1/ε^{\frac{1-n}{n}}$, attained for $β=\mathcal{O}(ε^{\frac{1-n}{n}})$, $n\in(0,1)$ being the exponent in the Carreau model. We illuminate this scaling enhancement and the geometric-rheological mechanism underlying it through asymptotic arguments and numerical simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2409_09374
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Giant superhydrophobic slip of shear-thinning liquids
Schnitzer, Ory
Ray, Prasun K.
Fluid Dynamics
We theoretically illustrate how complex fluids flowing over superhydrophobic surfaces may exhibit giant flow enhancements in the double limit of small solid fractions ($ε\ll1$) and strong shear thinning ($β\ll1$, $β$ being the ratio of the viscosity at infinite shear rate to that at zero shear rate). Considering a Carreau liquid within the canonical scenario of longitudinal shear-driven flow over a grooved superhydrophobic surface, we show that, as $β$ is decreased, the scaling of the effective slip length at small solid fractions is enhanced from the logarithmic scaling $\ln(1/ε)$ for Newtonian fluids to the algebraic scaling $1/ε^{\frac{1-n}{n}}$, attained for $β=\mathcal{O}(ε^{\frac{1-n}{n}})$, $n\in(0,1)$ being the exponent in the Carreau model. We illuminate this scaling enhancement and the geometric-rheological mechanism underlying it through asymptotic arguments and numerical simulations.
title Giant superhydrophobic slip of shear-thinning liquids
topic Fluid Dynamics
url https://arxiv.org/abs/2409.09374