The fluid mechanics of the ureter from a lubrication theory point of view

Lykoudis, Paul S.; Roos, R.

doi:10.1017/s0022112070002653

Cited by 66 publications

(55 citation statements)

References 7 publications

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“…Cognizant that they were not mimicing physiological systems exactly [9], these workers derived many useful results by analyzing idealized situations, designating one or more physical parameters as small or negligible to facilitate their study.…”

Section: Introductionmentioning

confidence: 99%

Peristaltic particle transport using the lattice Boltzmann method

et al. 2009

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Peristaltic transport refers to a class of internal fluid flows where the periodic deformation of flexible containing walls elicits a non-negligible fluid motion. It is a mechanism used to transport fluid and immersed solid particles in a tube or chan nel when it is ineffective or impossible to impose a favorable pressure gradient or desirous to avoid contact between the transported mixture and mechanical mov ing parts. Peristaltic transport occurs in many physiological situations and has myriad industrial applications. We focus our study on the peristaltic transport of a macroscopic particle in a two dimensional channel using the Lattice Boltzmann Method(LBM). We systematically investigate the effect of variation of the relevant dimensionless paJ'ameters of the system on the paJ·ticle transport. We find , among other results, a case where an increase of Reynolds number CaJl actually lead to a slight increase in particle transport, and a case where as the wall deformation•Author to whom correspondence should be addressed. Electronic mail: kconninl @jhu.edu 1 1 increases, the motion of the particle becomes non-negative only. VVe examine the particle behavior when the system exhibits the peculiar phenomenon of fluid tmp ping. Under these circumstances, the particle may itself become tmpped where it is subsequently transported at the wave speed, which is the ma.ximum possible transport in the absence of a favorable pressure gradient . Finally, we analyze how the particle presence affects stress, pressure, and dissipation in the fluid in hopes of determining preferred working conditions for peristaltic transport of shear-sensitive particles. We fiud that the levels of shear stress are most hazardous near the throat of the channel. We advise that shear-sensitive particles should be transported un der conditions where tmpping occurs as the particle is typically situated in a region of innocuous shear stress levels.

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Section: Introductionmentioning

confidence: 99%

Peristaltic particle transport using the lattice Boltzmann method

et al. 2009

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“…[11] If the total length of axon is L, the total rise in pressure is related to the rise in pressure per wavelength by AP= APxXo = APxnoL [12] With expressions [11] and [12], Eqs. [7] and [10] may be solved simultaneously for the theoretical operating flow rate or the theoretical mean flow speed.…”

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confidence: 99%

An Engineering Study of the Peristaltic Drive of Axonal Flow

Biondi

Levy

Weiß

1972

Proc. Natl. Acad. Sci. U.S.A.

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By determination of the rheological flow curve of minute quantities of axoplasm drawn into a microcapillary tube connected to a high vacuum, extruded axoplasm was shown to behave as a pseudoplastic fluid with a viscosity of 106-times that of water and without significant signs of time-dependent thixotropic or viscoelastic properties. A theoretical analysis of peristaltic pumping of such pseudoplastic fluids by sinusoidal surface waves was combined with experimental studies of a mechanical model designed to simulate peristaltic drive. The correlation of the respective data permitted quantitative predictions for the peristaltic mechanism of axonal flow, with speed being a function of peristaltic wave geometry and fluid properties, yielding a theoretical mean value of 0.45 mm/day, i.e., of the same order as that observed in the living nerve fiber.Axonal flow "refers to the fact that the 'axis cylinder' of the mature neuron keeps growing forth throughout life from its base in the cell body, its macromolecular substance being .... conveyed as a cohesive semisolid mass (18) toward the distal ending .... at a standard rate of the order of 1 mm per day, driven by a microperistaltic wave generated in the axonal surface" (1). Time-lapse motion pictures of live nerve fibers have recorded that wave (2), and the studies reported here are an attempt to define its properties and drive in physical terms. Thixotropic. A fluid that decreases in viscosity with fixed rates of shear as time increases, and has a tendency to take a set when at rest.

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“…The initial theoretical studies on peristalsis were carried out by Latham, 1 Shapiro et al, 2 Fung and Yih, 3 Lykoudis and Roos, 4 where either it is assumed that the amplitude of the peristaltic waves is low or the wavelength of the peristaltic waves is large. Later studies on the subject extended the previous ones to include inertial effects, 5,6 high Reynolds number effects, 7,8 creeping flow condition, 9 effects of peripheral layers 10 etc.…”

Section: Introductionmentioning

confidence: 99%

Simulations of peristaltic slip-flow of hydromagnetic bio-fluid in a curved channel

2016

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The influence of slip and magnetic field on transport characteristics of a bio-fluid are analyzed in a curved channel. The problem is modeled in curvilinear coordinate system under the assumption that the wavelength of the peristaltic wave is larger in magnitude compared to the width of the channel. The resulting nonlinear boundary value problem (BVP) is solved using an implicit finite difference technique (FDT). The flow velocity, pressure rise per wavelength and stream function are illustrated through graphs for various values of rheological and geometrical parameters of the problem. The study reveals that a thin boundary layer exists at the channel wall for strong magnetic field. Moreover, small values of Weissenberg number counteract the curvature and make the velocity profile symmetric. It is also observed that pressure rise per wavelength in pumping region increases (decreases) by increasing magnetic field, Weissenberg number and curvature of the channel (slip parameter).

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The fluid mechanics of the ureter from a lubrication theory point of view

Cited by 66 publications

References 7 publications

Peristaltic particle transport using the lattice Boltzmann method

Peristaltic particle transport using the lattice Boltzmann method

An Engineering Study of the Peristaltic Drive of Axonal Flow

Simulations of peristaltic slip-flow of hydromagnetic bio-fluid in a curved channel

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