Journal ArticleDOI
Viscoplastic flow around a cylinder in an infinite medium
TLDR
In this article, numerical simulations were carried out to determine the flow characteristics of a Herschel-Bulkley viscoplastic fluid around a cylinder in an infinite medium, and the location, dimension and kinematics of the rigid zones were determined.Abstract:
The purpose of the numerical simulations carried out in this study is to determine the flow characteristics of a Herschel–Bulkley viscoplastic fluid around a cylinder in an infinite medium. Inertia is assumed to be negligible. Two types of boundary conditions are considered: the fluid adheres or slips (zero tangential stress) on the cylinder wall. Finite-element modelling involves regularising the Herschel–Bulkley model, as proposed by Papanastasiou [J. Rheol. 31 (1987) 385]. The effect of the yield stress value and shear-thinning index on the kinematic field and drag exerted on the cylinder were explored systematically. The location, dimension and kinematics of the rigid zones were determined. The results are compared with available theoretical data.read more
Citations
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Journal ArticleDOI
Yielding to Stress: Recent Developments in Viscoplastic Fluid Mechanics
TL;DR: The most common idealization of a viscoplastic fluid is the Bingham model, which has been widely used to rationalize experimental data, even though it is a crude oversimplification of true rheological behavior.
Journal ArticleDOI
On the usage of viscosity regularisation methods for visco-plastic fluid flow computation
Ian Frigaard,Chérif Nouar +1 more
TL;DR: In this paper, the authors examined convergence of regularised solutions to those of the corresponding exact models, in both mathematical and physical senses, to give practical guidance as to the order of error that one might expect for different regularisations and for different types of flow.
Flows of viscoplastic materials: models and computations
TL;DR: In this paper, a continuation parameter is introduced into the models to facilitate the solution process and produces virtually the same results as the ideal models by the right choice of its value, which can be used to track down yielded/unyielded regions.
Journal ArticleDOI
Viscoplastic Matrix Materials for Embedded 3D Printing
Abigail K. Grosskopf,Ryan L. Truby,Hyoungsoo Kim,Hyoungsoo Kim,Antonio Perazzo,Jennifer A. Lewis,Howard A. Stone +6 more
TL;DR: This work investigates the effects of matrix viscoplasticity on the EMB3D printing process and determines that scaling relationships based on the Oldroyd number, Od, exist between these dimensions and the rheological properties of the matrix materials and printing parameters.
Journal ArticleDOI
Very slow flow of Bingham viscoplastic fluid around a circular cylinder
TL;DR: In this article, numerical simulations have been used to study the flow of a Bingham viscoplastic fluid around a circular cylinder in an infinite medium with negligible inertia effects, and Papanastasiou's regularization technique has been adopted to approximate the model.
References
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Book
Low Reynolds number hydrodynamics
John Happel,Howard Brenner +1 more
TL;DR: Low Reynolds number flow theory finds wide application in such diverse fields as sedimentation, fluidization, particle-size classification, dust and mist collection, filtration, centrifugation, polymer and suspension rheology, and a host of other disciplines.
Journal ArticleDOI
Flows of Materials with Yield
TL;DR: In this article, a modified constitutive relation that applies everywhere in the flow field, in both yielded and practically unyielded regions, is proposed to analyze two-dimensional flows of Bingham fluids.
Journal ArticleDOI
The yield stress—a review or ‘παντα ρει’—everything flows?
TL;DR: In this paper, the authors give an account of the development of the idea of yield stress for solids, soft solids and structured liquids from the beginning of this century to the present time.
Journal ArticleDOI
A review of the slip (wall depletion) of polymer solutions, emulsions and particle suspensions in viscometers: its cause, character, and cure
TL;DR: Slip occurs in the flow of two-phase systems because of the displacement of the disperse phase away from solid boundaries as mentioned in this paper, which arises from steric, hydrodynamic, viscoelastic and chemical forces and constraints acting on the dispersed phase immediately adjacent to the walls.
Book
Bubbles, Drops, and Particles in Non-Newtonian Fluids
TL;DR: In this paper, the authors present a detailed discussion of non-Newtonian fluid behavior in the context of Viscoelastic Fluid Dynamics, including the role of velocity-volume behavior in free rise or fall.