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Viscoplastic Couette Flow in the Presence of Wall Slip with Non-Zero Slip Yield Stress
(2019)
The steady-state Couette flow of a yield-stress material obeying the Bingham-plastic constitutive equation is analyzed assuming that slip occurs when the wall shear stress exceeds a threshold value, the slip (or sliding) ...
The PAL (Penalized Augmented Lagrangian) method for computing viscoplastic flows: A new fast converging scheme
(2018)
Computation of viscoplastic fluid flows has always been a challenging task. Viscoplastic models are intrinsically discontinuous at the yielded-unyielded interface, which leads to numerical difficulties, because of the ...
Annular pressure-driven flow of a Bingham plastic with pressure-dependent rheological parameters
(2019)
The pressure and temperature dependence of the yield stress is well established in oil drilling. In the present work, the steady, annular pressure-driven flow of a Bingham plastic is considered under the assumption that ...
Start-up plane Poiseuille flow of a Bingham fluid
(2019)
The start-up flow of a Bingham plastic in a channel is considered and Safronchik’s solution [1] for the initial evolution of the yield surface and the core velocity is revisited. Stricter time bounds for the validity of ...
The time-dependent extrudate-swell problem of an Oldroyd-B fluid with slip along the wall
(1998)
We demonstrate that viscoelasticity combined with nonlinear slip acts as a storage of elastic energy generating oscillations of the pressure drop similar to those observed experimentally in extrusion instabilities. We ...
Predictions of structure breakdown, buildup and shear banding in semisolid suspensions
(2008)
When SSM material is subjected to a sudden transient the rate of buildup (aging) is negligible compared to the rate of breakdown (shear rejuvenation). While this is generally true, due to prolonged processing or the geometry ...
Shear rejuvenation, aging and shear banding in yield stress fluids
(2009)
The purpose of this work is to simulate shear rejuvenation and aging effects in shear thinning yield stress fluids in a typical rotational rheometer and to provide a common framework to describe the behavior of yield stress ...
Rheological effects of strusture breakdown in semisolid slurries
(2004)
An essential element for the integration of the semisolid metal (SSM) process in the production of complex commercial components is the availability of accurate mathematical and computational tools that could describe both ...