Axial flows in generalized ducts are analyzed for viscoplastic materials behaving as Bingham plastics with a yield stress. A constitutive equation proposed by Papanastasiou is used, which applies everywhere in the flow field in both yielded and

some ﬂuid dynamic researchers, during their experiments, found substances that are recognized as viscoplastic materials, which require a certain threshold stress level for their deformation.

We examine the internal flow of viscoplastic liquids through ducts consisting of an abrupt axisymmetric expansion followed by an abrupt contraction. Steady, inertialess numerical solutions were obtained by solving the conservation equations of mass and momentum via the finite volume method. Membrane viscoplastic flow. Evans EA, Hochmuth RM. In this paper, a theory of viscoplasticity formulated by Prager and Hohenemser is developed for a two-dimensional membrane surface and applied to the analysis of the flow of "microtethers" pulled from red blood cells attached to glass substrates. A theoretical study is presented of the flow of viscoplastic fluid through a Hele-Shaw cell that contains various kinds of obstructions.

Viscoplastic flow

We have modeled an incompressible, non-isothermal flow of a magnetohydrodynamic (MHD) viscoplastic fluid when it passes through the tapered area between two co-rotating rolls. The basic conservation equations like mass, momentum, and energy based on the lubrication approximation theory (LAT) are developed, non-dimensionalized, and solved exactly for the velocity-, pressure gradient-, and 2019-09-12 · A. Wachs, “ Computational methods for viscoplastic fluid flows,” in Lectures on Visco-Plastic Fluid Mechanics (Springer, 2019), pp. 83– 125. Google Scholar Crossref; 19. L. Muravleva, “ Axisymmetric squeeze flow of a viscoplastic Bingham medium,” J. Non-Newtonian Fluid Mech. 249, 97– 120 (2017). Low shear rate magnetorheology was used in order to determine flow behavior; the yield stress obtained as a parameter of different viscoplastic models was evaluated.

Rheological studies concerning natural muddy debris flows have shown that these materials can be modelled as non-Newtonian viscoplastic fluids.

viscoplastic energy maximization level set method for two-fluid flow, through an interface correction technique”. Modelling of Flexible Fibres in Viscous Fluid Flow (2019) On the Interaction of Side-By-Side Circular Cylinders in Viscoplastic Fluids (2019).

We focus on viscoplastic and elastoviscoplastic flows to reveal some differences and similarities between these two classes of flows. Small elastic effects increase the pressure drop and also the size of unyielded regions in the flow which is the consequence of different stress solutions compare to viscoplastic flows.

Especially, a very simple Chaboche- In particular, viscoplastic fluids present the awkward feature of a yield stress, which can cause the fluid to clog up the conduit or medium and interfere with flow . Oct 25, 2015 The flow of a yield stress fluid through a fracture is studied computationally and analyticaly.

Here, an analytical solution of the equation of motion for the axial flow of an incompressible viscoplastic fluid (represented by the Hershel–Bulkley equation) in a long concentric annulus under isothermal, fully 2021-03-26 Abstract Drag flow past circular cylinders concentrically placed in a tube filled with viscoplastic fluids, obeying the Herschel–Bulkley model, is analyzed via numerical simulations with the finite element method. The purpose it to find limiting drag values for cessation of motion of the object in steady flow.
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Fig 1 : Simulation of the propa- Yielded and unyielded zones that exist in viscoplastic flow due to varying shear rate profile in an annulus are not considered while modeling flow. This thesis investigates the factors affecting the existence of plug zones and the effect of plug zones on a fluid’s cuttings carrying capacity and on annular pressure drop. A classification of flowfields for the flow of a Bingham fluid in general eccentric annular geometries is presented. Simple arguments show that a singularity can exist in the stress gradient on boundaries between zones with yielded and un-yielded fluid respectively.

From a rheological perspective, the primary difference between a viscoplastic and viscoelastic material is the presence of a yield stress.
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Cite this entry as: (2020) Viscoplastic Flow. In: Altenbach H., Öchsner A. (eds) Encyclopedia of Continuum Mechanics. Springer, Berlin, Heidelberg. https://doi.org

Instantaneous power consumption of the damper (blue, solid line) and rate of energy dissipation due to fluid deformation (red, dashed line) for different oscillation frequencies. For details see the caption of Fig. 12 .

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A CFD (computational fluid dynamics) analysis was carried out for the Bingham viscoplastic fluid flow simulations around cylinders of circular and square shapes. The governing equations in space were discretized with the finite element approach via a weak formulation and utilizing Ladyzhenskaya–Babuška–Brezzi-stable pair Q 2 / P 1 disc for approximation of the velocity and

Lubrication theory is used for shallow and slow flows to reduce the governing equations to a non-linear diffusion-type equation for the local fluid depth; this model is used as the basis for exploration of the problem. See Viscoplastic general flow rule for the specific definition of each quantity. The base class implementation by default provides zero for the and the quantities, giving a standard model that evolves only in proportion to the inelastic strain rate. AXIAL FLOW OF GENERALIZED VISCOPLASTIC FLUIDS IN NON-CIRCULAR DUCTS. Chemical Engineering Communications 1998, 168 (1) , 13-43.

In this book, we shall consider the kinematics and dynamics of the flows of fluids exhibiting a yield stress. To highlight the principal characteristics of such fluids,

For details see the caption of Fig. 12 . (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article). - "Viscoplastic flow in an extrusion FLOW-3D includes viscoelastic flow models that predict the behavior of material that behave both like liquids and solids, depending on the local strain and strain rate. Viscoelastic materials include polymer solutions, melts, and highly filled suspensions of particles. Elasto-viscoplastic materials exhibit solid-like behavior up to a yield stress limit, beyond which the material exhibits The lateral portions of the flow near the aperture become almost stationary (as indicated by the relatively low yield surface and the vectors of the depth-integrated Shallow viscoplastic flow on an inclined plane 11 6 No motion 5 Transient flow 4 Developing streams … Axial flows in generalized ducts are analyzed for viscoplastic materials behaving as Bingham plastics with a yield stress. A constitutive equation proposed by Papanastasiou is used, which applies everywhere in the flow field in both yielded and Electroosmotic Flow of Viscoplastic Fluids Through a Slit Microchannel Chiu-On Ng* and Cheng Qi# Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong *Corresponding author: Tel: +852 28592622, Fax: +852 28585415, E-mail: cong@hku.hk # Presenter: E-mail: u3001746@connect.hku.hk Under the action of a pressure gradient, a solid body B penetrates into another body.

Project: Simulation of viscoplastic flows with the 2021-03-05 flow of a viscoplastic medium through a capillary section under a stationary pressure drop. Based on the order of determining equivalent viscosity described above, we will solve We examine the internal flow of viscoplastic liquids through ducts consisting of an abrupt axisymmetric expansion followed by an abrupt contraction. Steady, inertialess numerical solutions were obtained by solving the conservation equations of mass and momentum via the finite volume method. The viscoplastic behavior of the liquid was modeled by the generalized Newtonian liquid model with a Actually little is known on the physical processes involved in avalanches or debris flows.