Viscoplastic materials are fluids that exhibit a yield stress: below a certain critical shear stress there is no deformation of the fluid and it behaves like a rigid solid, but when that yield value is exceeded, the material flows like a fluid.

An experimental study was conducted to measure the settling velocity of spherical particles in viscoplastic fluids. Using a mechanistic model based on the balance of the forces acting on the settling particle and detailed statistical analyses of the experimental results, a generalized model for predicting settling velocity of spherical particles in viscoplastic fluids was developed.

The archetypal feature of a viscoplastic fluid is its yield stress: If the material is not sufficiently stressed, it behaves like a solid, but once the yield stress is exceeded, the material flows like a fluid. Such behavior characterizes materials common in industries such as petroleum and chemical processing, cosmetics, and food processing and in geophysical fluid dynamics. The most common The slipping effect during creeping flow of viscoplastic fluids around a circular cylinder has been investigated via numerical simulations. For the bulk behavior of the fluid, a Herschel-Bulkley 2018-10-11 The archetypal feature of a viscoplastic fluid is its yield stress: If the material is not sufficiently stressed, it behaves like a solid, but once the yield stress is exceeded, the material flows like a fluid. Such behavior characterizes materials common in industries such as petroleum and chemical processing, cosmetics, and food processing and in geophysical fluid dynamics. The most common Viscoplastic fluid mixing in a rotating tank.

Viscoplastic fluids

Examples of constitutive equations obtained using both procedures are presented. We show that irrespective of the method used, it is not possible to obtain consistent viscoplastic fluid formulations starting from certain yield functions. Comparisons between the response of the proposed models for uniaxial compression conditions is provided. We experimentally study the viscous fingering problem of viscoplastic fluids in channels of rectangular cross section. We find that a yield stress-dependent capillary number (${\text{Ca}}^{*}$) and an aspect ratio-dependent Bond number (${\text{Bo}}^{*}$) can classify the finger shape into ramified and unified fingering patterns, and the finger flow regime into yield stress, viscosity, and Helical flow of viscoplastic Herschel‐Bulkley fluids in concentric and eccentric annuli with rotating inner cylinder was investigated numerically. Similar flows occur in drilling operations of oil and gas wells.

drilling fluid is typically a viscoplastic fluid of pseudoplastic nature whose viscosity of viscoplastic fluids in concentric, eccentric, as well as irreg- ular eccentric

This leads to a critical ratio of the buoya Fluids 2019, 4, 93 3 of 13 forces at small gap distances, they found a remarkable reduced drag force comparing to the single cylinder. For the lift coe cient variation with the gap distance, they found a sigmoidal pattern. On the topic of viscoplastic ﬂuid ﬂow … This class of materials is called viscoplastic fluids.

Drilling fluid, an example of a viscoplastic fluid, is a type of non-Newtonian fluid characterized by the existence of a threshold stress, called yield stress, that must be overcome for fluids to flow. Drilling fluid is conventionally modeled using power law parameters and yield stress.

The constitutive models most often used to describe a viscoplastic fluid are the Bingham con-stitutive model [1] or the slightly more general Herschel-Bulkley constitutive model (2.8)-(2.9). The deformation and flow behavior of viscoplastic fluids can be realistically represented with the Herschel-Bulkley constitutive equation, which we have utilized as the basis for the development Thixotropic elasto-viscoplastic model for structured fluids P. R. de Souza Mendes, Soft Matter , 2011, 7 , 2471 DOI: 10.1039/C0SM01021A Here, analytical solutions are developed for the constant‐speed squeezing flow of viscoplastic fluids. It is assumed that the fluid is purely viscous, and hence viscoelastic effects unimportant. The rheological behavior of the viscoplastic fluids is represented by the Herschel‐Bulkley viscosity function.

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2, s. Within the EU project YIELDGAP, we are looking for 3 PhD students to study viscoplastic and elastoviscoplastic fluids. We plan experiments, numerical Very often the mechanical behavior of the liquids involved is viscoplastic, as is of non-Newtonian fluids through the different geometries that are representative Highly parallelisable simulations of time-dependent viscoplastic fluid flow with structured Numerical simulations of immiscible generalised Newtonian fluids.

Viscoplastic Fluids: From Theory to Application. Edited by Neil J. Balmforth, John R. de Bruyn, Monica F. Naccache. Volume 193, Pages 1-154 (March 2013) Download full Abstract. Bingham fluids constitute a very important class of non-Newtonian fluids.
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Abstract The archetypal feature of a viscoplastic fluid is its yield stress: If the material is not sufficiently stressed, it behaves like a solid, but once the yield stress is exceeded, the material flows like a fluid.

The deformation and flow behavior of viscoplastic fluids can be realistically represented with the Herschel-Bulkley constitutive equation, which we have utilized as the basis for the development Thixotropic elasto-viscoplastic model for structured fluids P. R. de Souza Mendes, Soft Matter , 2011, 7 , 2471 DOI: 10.1039/C0SM01021A Here, analytical solutions are developed for the constant‐speed squeezing flow of viscoplastic fluids. It is assumed that the fluid is purely viscous, and hence viscoelastic effects unimportant. The rheological behavior of the viscoplastic fluids is represented by the Herschel‐Bulkley viscosity function. Regarding the viscoplastic fluid flow past triple cylinders (as mentioned in the Introduction), to the best of the authors’ knowledge, this is the first study that examines the interaction between the cylinders and the unyielded regions around the objects in the presence of the viscoplastic fluid.

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55, no. 2, s. Within the EU project YIELDGAP, we are looking for 3 PhD students to study viscoplastic and elastoviscoplastic fluids. We plan experiments, numerical Very often the mechanical behavior of the liquids involved is viscoplastic, as is of non-Newtonian fluids through the different geometries that are representative Highly parallelisable simulations of time-dependent viscoplastic fluid flow with structured Numerical simulations of immiscible generalised Newtonian fluids. problems of visco-plastic fluids.

Albert Magnin The 3rd meeting on “Viscoplastic Fluids: From Theory to Application” was held in the lovely coastal city of Limassol, Cyprus. It was organized by the Hellenic Society of Rheology, under the auspices of ESR, with the help and encouragement of Neil Balmforth and Ian Frigaard, who organized the 1st meeting held in Banff, Canada (22–27 October 2005). 2.1. Experimental set-up. A schematic of a viscoplastic drop on an inclined superhydrophobic surface is shown in figure 1.The superhydrophobic surface was fabricated by coating paraffin-wax-fixed candle soot on a glass slide (static contact angle of deionized water: $162\pm 2^{\circ }$) (Seo, Kim & Kim Reference Seo, Kim and Kim 2014).Viscoplastic fluids were prepared by mixing xanthan gum 2016-10-27 2019-09-12 2019-12-10 Drilling fluid, an example of a viscoplastic fluid, is a type of non-Newtonian fluid characterized by the existence of a threshold stress, called yield stress, that must be overcome for fluids to flow. Drilling fluid is conventionally modeled using power law parameters and yield stress. 2010-01-01 Mixing Viscoplastic Fluids in Stirred Vessels Over Multiple Scales: Experiment vs.