Some Applications of Magnetic Resonance Imaging in Fluid Mechanics: Complex Flows and Complex Fluids

Bonn, Daniel; Rodts, Stéphane; Groenink, Maarten; Rafaı̈, Salima; Shahidzadeh-Bonn, Noushine; Coussot, Philippe

doi:10.1146/annurev.fluid.40.111406.102211

Cited by 99 publications

(73 citation statements)

References 73 publications

(82 reference statements)

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“…This value was divided by the signal intensity obtained at rest to give the radial distribution of the relative volume fraction of oil, and hence u(r)/u o . MRI resolution is insufficient to obtain reliable results within the first few grain distances from the cylinder surfaces Using well-established techniques, one can also access the radial variation of the local velocity in the flowing system [Bonn et al (2008) Fig. 1 (left).…”

Section: Dry Granular Systems and The Fluidity Modelmentioning

confidence: 99%

Local rheology of suspensions and dry granular materials

Cagny¹,

Fall

Denn

et al. 2015

Journal of Rheology

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General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. AbstractThe flow of dry and wet granular media is investigated in a Couette geometry using magnetic resonance imaging in order to test the applicability of the "fluidity model" for nonlocality in these materials. Local volume fraction measurements show that the systems become heterogeneous during flow. We find that the nonlocal rheology of suspensions can be correlated using the fluidity model, but the length scale that emerges is not a material property and the model cannot be used for predictive purposes. Rather, the suspension behavior is fully explained as a consequence of stress-driven particle migration and the resulting concentration gradient. The conclusion is less strong for the dry granular system, but it appears likely that the apparent nonlocal behavior is simply due to the formation of a shear band caused by granular dilatancy. V C 2015 The Society of Rheology.[http://dx

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Section: Dry Granular Systems and The Fluidity Modelmentioning

confidence: 99%

Local rheology of suspensions and dry granular materials

Cagny¹,

Fall

Denn

et al. 2015

Journal of Rheology

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“…The understanding of complex fluids is of enormous importance for many practical applications [3] and the theory touches on many branches of physics. Recent advances make it possible to follow the suspension local velocity during a standard rheological experiment [4,5]. Quantifying the local flow field simultaneously with rheological measurements gives the possibility to measure both the intrinsic and apparent rheology.…”

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Transient shear banding in time-dependent fluids

et al. 2013

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We study the dynamics of shear-band formation and evolution using a simple rheological model. The description couples the local structure and viscosity to the applied shear stress. We consider in detail the Couette geometry, where the model is solved iteratively with the Navier-Stokes equation to obtain the time evolution of the local velocity and viscosity fields. It is found that the underlying reason for dynamic effects is the nonhomogeneous shear distribution, which is amplified due to a positive feedback between the flow field and the viscosity response of the shear thinning fluid. This offers a simple explanation for the recent observations of transient shear banding in time-dependent fluids. Extensions to more complicated rheological systems are considered. The property that characterizes complex fluids is their nontrivial rheology, shear rate-stress relation. They are generally further categorized into shear thinning or shear thickening fluids. Both cases are additionally complicated by time dependence. Due to the stress-shear interaction, already small perturbations in the local stress can result in a positive feedback with the flow promoting shear instabilities in each case [1,2]. The understanding of complex fluids is of enormous importance for many practical applications [3] and the theory touches on many branches of physics. Recent advances make it possible to follow the suspension local velocity during a standard rheological experiment [4,5]. Quantifying the local flow field simultaneously with rheological measurements gives the possibility to measure both the intrinsic and apparent rheology. This has led to the discovery that a heterogeneous shear distribution in samples during such tests is ubiquitous. Shear banding [6] has been observed in many systems composed of substantially different building blocks, such as colloidal glasses, wormlike micelles, foams, and granular matter [7]. The current viewpoint, both phenomenologically and theoretically, is that a nonmonotonic intrinsic flow curve is what is common to most of these materials [6,8], but also other mechanisms have been suggested [9].A branch of complex fluids are the simple yield stress fluids [10]. These materials do not show aging phenomena (thixotropy). Therefore, they are expected to have a monotonic intrinsic flow curve and a steady state without shear bands [11]. However, recent experiments [12] display shear banding during startup flows in a rotational rheometer indicating timedependent behavior. These so called transient shear bands can be very long lasting, but eventually vanish with a homogeneous steady state. The transient shear banding phenomenon tests our fundamental understanding of non-Newtonian fluids, and is also important for industrial processes and simply for understanding usual rheological measurements. A particular feature of the transient shear banding is that it appears to exhibit scaling familiar from critical phenomena: The time it takes for the transient to disappear (fluidization time τ f ) is a power-law functi...

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“…We further argue that this range can be extended to 10 À3 S/m under industrial and to 10 À6 S/m under laboratory conditions making LFV applicable to most liquids of practical interest. In spite of remarkable advances in flow measurement, [1][2][3][4] it is currently impossible to measure the flow rate of tap water in a copper pipe without mechanical contact between the flowmeter and the pipe. Whereas, metering of tap water does not represent a grand scientific challenge, there are a variety of less mundane situations where noncontact flow measurement through opaque walls or in opaque liquids would be highly desirable.…”

mentioning

confidence: 99%

A universal noncontact flowmeter for liquids

Wegfraß

Diethold

Werner

et al. 2012

Applied Physics Letters

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Lorentz force velocimetry (LFV) is a noncontact electromagnetic flow measurement technique for liquid metals that is currently used in fundamental research and metallurgy. Up to now, the application of LFV was limited to the narrow class of liquids whose electrical conductivity is of the order 106 S/m. Here, we demonstrate that LFV can be applied to liquids with conductivities up to six orders of magnitude smaller than in liquid metals. We further argue that this range can be extended to 10−3 S/m under industrial and to 10−6 S/m under laboratory conditions making LFV applicable to most liquids of practical interest.

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Some Applications of Magnetic Resonance Imaging in Fluid Mechanics: Complex Flows and Complex Fluids

Cited by 99 publications

References 73 publications

Local rheology of suspensions and dry granular materials

Local rheology of suspensions and dry granular materials

Transient shear banding in time-dependent fluids

A universal noncontact flowmeter for liquids

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