Journal ArticleDOI
Sink flows of a suspension of rigid rods
J.M. Rallison,R.A. Keiller +1 more
TLDR
In this article, the flow of a suspension of rigid rods in a wedge of small angle is considered and the small scale structure within these zones is determined, and matched asymptotic expansions are used to provide jump conditions across them.Abstract:
The flow of a suspension of rigid rods in a wedge of small angle is considered. In the lubrication limit when the angular width of the channel is small but the rod concentration is high it is found that wedges of fluid (here called stagnant zones ) in the interior of the channel become asymptotically static. The small scale structure within these zones is determined, and matched asymptotic expansions are used to provide jump conditions across them. These results are found to show good agreement with exact solutions for wedge flows even when the angular half-width of the wedge is not small (up to 30°, say). Analogous jump conditions are devised for stagnant zones in general planar lubrication flows of rigid rod suspensions.read more
Citations
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The rheology of fibre suspensions
TL;DR: Theoretical and experimental work on the rheology of suspensions of slender fibres is reviewed in this article, where the main practical drawback of dilute suspension theory is that fibres have to be far apart on a scale based on the length of the fibres rather than their diameter, and so dilute means extremely dilute in terms of the volume fraction of solids in the suspension.
Journal ArticleDOI
Chaotic rotation of triaxial ellipsoids in simple shear flow
TL;DR: In this article, an analytic theory explaining the onset of chaotic rotation is proposed, and the chaotic rotation coexists with periodic and quasi-periodic motions, depicted by regular closed loops and islands in the system Poincare map.
Journal ArticleDOI
Investigation of the abrupt contraction flow of fiber suspensions in polymeric fluids
TL;DR: In this article, numerical simulations of the flow of rigid fibres through a 4:1 planar contraction are presented, and the predicted flow pattern and fiber orientation are used to examine the nature of the suspending matrix which may consist of either a Newtonian fluid or a polymer melt.
Chaotic rotation of triaxial ellipsoids in simple shear flow
TL;DR: Szeri et al. as discussed by the authors studied the dynamics of a general triaxial ellipsoidal particle with one axis significantly longer than two others and showed that chaotic rotation coexists with periodic and quasi-periodic motions.
Journal ArticleDOI
Entry flow of fiber suspensions in a straight channel
Lan Tang,M. Cengiz Altan +1 more
TL;DR: In this article, the effects of Reynolds number, Re, and a non-dimensional suspension parameter, C, on the developing velocity and orientation fields are investigated, and it is found that both the second and fourth-order orientation evolution equations, if used with quadratic closure approximations, inaccurately predict an earlier alignment of fibers in the flow direction.
References
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Journal ArticleDOI
The stress generated in a non-dilute suspension of elongated particles by pure straining motion
TL;DR: In this article, the authors investigated the effect of interactions between rigid particles in a dilute suspension and showed that the contribution of particles to the bulk stress due to the interactions between them is relatively large, for volume fractions which are still small.
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The flow of fiber suspensions in complex geometries
TL;DR: In this paper, a continuum theory for dilute suspensions of large-aspect-ratio particles is applied to the flow of fiber suspensions through contractions, which incorporates the statistical orientation distribution function into the stress equation.
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Flow regimes for fiber suspensions in narrow gaps
TL;DR: In this paper, the flow of fiber suspensions in narrow gaps is examined using rheological theories for suspensions of rigid particles in a Newtonian solvent, and a dimensionless particle number Np describes the intrinsic anisotropy of the suspension order-of-magnitude estimates are developed for the velocity, stress and fiber orientation components in a narrow gap of slowly varying thickness.
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High-Deborah-number flows of dilute polymer solutions
TL;DR: In this paper, a boundary layer approximation is developed for steady flows of dilute polymer solutions at high Deborah numbers, where polymer molecules are most highly extended within thin elongated regions at or downstream of stagnation points.
Journal ArticleDOI
The viscosity-volume fraction relation for suspensions of rod-like particles by falling-ball rheometry
TL;DR: In this article, the authors measured the relative viscosities of suspensions of randomly oriented rods in a Newtonian fluid using falling-ball rheometry, and found that the specific viscosity increased with the cube of the volume fraction.