# Outi Tammisolas publikationer - KTH

Artificial Thermal Ageing of Polyester Reinforced and - JoVE

One of the main features of these types of flows is the nonlinear relation between the shear stress and the shear rate. Here, we focus on fluids that can exhibit simultaneously elastic, viscous and plastic properties, usually called elastoviscoplastic (EVP) fluids (Balmforth, Frigaard & Ovarlez 2014). International audienceFrom a thermodynamic theory, a new model for elastoviscoplastic fluid flow is presented. It extends the Bingham viscoplastic model and the Oldroyd viscoelastic model. Fundamental flows are studied: simple shear flow, uniaxial elongation and large amplitude oscillatory shear.

However, in this case the stress depends both on the plastic strain rate and on the plastic strain itself. Viscoplastic ﬂuid Elastoviscoplastic ﬂuid 1 Introduction Non-Newtonian ﬂuid ﬂows in porous media are of great practical importance for numerous industries A constitutive model for structured fluids is presented. Its predictive capability includes thixotropy, viscoelasticity and yielding behavior. It is composed by two differential equations, one for the stress and the other for the structure parameter—a scalar quantity that represents the structuring level of 1.3 Elastoviscoplastic fluid. Despite the numerous studies performed to analyse viscoelastic turbulent flows, much less attention has been given to viscoplastic and elastoviscoplastic fluids. Various fluids of practical interest, such as liquid foams, droplet emulsions or blood, present such elastoviscoplastic behavior: at low stress, the material behaves as a viscoelastic solid, whereas at stresses above a yield stress, the material behaves as a fluid. Yet, the velocity fields in the viscoplastic and elastoviscoplastic flows are comparable for small elastic effects.

## 23339 Kápa á skýrslu Vegagerðar.FH11

Fundamental flows are studied: simple shear flow, uniaxial elongation and large amplitude oscillatory shear. We model the rheological behavior of the yield-stress fluid using the recently developed elastoviscoplastic constitutive equation that takes into account the elastic and viscoplastic deformations Viscoplastic fluids exhibit a threshold in applied stress (yield stress) below which the material behaves like an elastic solid, and above which it flows like a liquid. Bubbles are therefore harder to remove from a viscoplastic fluid than from a simple viscous fluid: in the regime where the material behaves like a solid, the bubbles are The collision of drops in a solid substrate is an interesting problem with several practical applications. When the drop is made of a complex fluid the problem presents numerical challenges due to the interaction of the mechanical properties and the free surface approach.

### Outi Tammisolas publikationer - KTH

It extends the Bingham viscoplastic model and the Oldroyd viscoelastic model. Fundamental flows are studied: simple shear flow, uniaxial elongation and large amplitude oscillatory shear. We model the rheological behavior of the yield-stress fluid using the recently developed elastoviscoplastic constitutive equation that takes into account the elastic and viscoplastic deformations Viscoplastic fluids exhibit a threshold in applied stress (yield stress) below which the material behaves like an elastic solid, and above which it flows like a liquid.

1 Introduction.

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An analytical study of elastoviscoplastic fluid flow in tubes of non-circular cross section is presented. The constitutive structure of the fluid is described by a linear frame invariant combination of the Phan-Thien−Tanner model of viscoelastic fluids and the Bingham model of plastic fluids. One of the main features of these types of flows is the nonlinear relation between the shear stress and the shear rate. Here, we focus on fluids that can exhibit simultaneously elastic, viscous and plastic properties, usually called elastoviscoplastic (EVP) fluids (Balmforth, Frigaard & Ovarlez 2014). International audienceFrom a thermodynamic theory, a new model for elastoviscoplastic fluid flow is presented. It extends the Bingham viscoplastic model and the Oldroyd viscoelastic model.

When the drop is made of a complex fluid the problem presents numerical challenges due to the interaction of the mechanical properties and the free surface approach. In the present work, we solve the numerical problem of elasto-viscoplastic drops colliding in vertical plane. The free
To predict the complex transient rheology of thixotropic elasto-viscoplastic (TEVP) fluids, we generalize a previous scalar thixotropic-only “multi-lambda” (ML) model and combine it with the isotropic kinematic hardening (IKH) model. The Herschel–Bulkley rheological fluid model includes terms representing viscosity and plasticity. In this classical model, below the yield stress the material is strictly rigid. Complementing this model by including elastic behavior below the yield stress leads to a description of an elastoviscoplastic (EVP) material such as an emulsion or a liquid foam. We include this modification in a
A new elastoviscoplastic model based on the Herschel-Bulkley viscoplastic model Pierre Saramito To cite this version: Pierre Saramito.

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Mendes, Flow of elasto-viscoplastic thixotropic liquids Journal of Non-Newtonian Fluid Mechanics journal homepage: www.elsevier. com/locate/jnnfm. The “avalanche effect” of an elasto-viscoplastic thixotropic Post Doc., Aalto University, Finland - Cited by 282 - Computational fluid Computational modeling of multiphase viscoelastic and elastoviscoplastic flows. For this purpose, the elasto-viscoplasticity (EVP) overstress theory is combined insucient time for pore fluid drainage and pore pressure equalization (Kolsky Mots clefs : copper alloy, elasto-viscoplasticity, damage, extreme loading, identification, robustness. 1 Introduction.

This numerical study focuses on regularised Bingham-type and viscoelastoplastic fluids, performing simulations for 4:1:4 contraction–expansion flow with a hybrid finite element–finite volume subcell scheme. The work explores the viscoplastic regime, via the Bingham–Papanastasiou model, and extends this into the viscoelastoplastic regime through the Papanastasiou–Oldroyd model. Our
Abstract An analytical study of the forced convection of an elastoviscoplastic fluid in tubes of arbitrary cross section is presented. The constitutive structure of the fluid is described by a frame indifferent linear combination of the Modified Phan-Thien-Tanner model of non-linear viscoelastic fluids and the Bingham model of non-linear plastic fluids.

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### Calidad del aire en Ikot Ekpene

presented for two complex fluids, a pseudoplastic shear-thinning xanthan gum solution and an elastoviscoplastic invert-emulsion drilling fluid. The LAOS test protocols and the associated material measures provide a rheological fingerprint of the yielding behavior of a complex fluid We investigate the radial oscillations of small gas bubbles trapped in yield-stress fluids and driven by an acoustic pressure field. We model the rheological behavior of the yield-stress fluid using the recently developed elastoviscoplastic constitutive equation that takes into account the elastic and viscoplastic deformations of the material [Saramito, J. Non-Newton. 2013-11-12 · of a Viscoplastic Fluid Raazesh Sainudiiny yDepartment of Mathematics and Statistics Viscoplastic ßuids Elastoviscoplastic ßuids Internal microstructure Near β titanium alloys can now compete with quasi-α or α/β titanium alloys for airframe forging applications. The body-centered cubic β-phase can represent up to 40% of the volume. However, the way that its elastic anisotropy impacts the mechanical behavior remains an open question.

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### Yield-stress fluids in porous media : a comparison of - DiVA

Originally it was believed that YS materials are just generalized Newtonian fluids, i.e. fluids with a viscosity that depends on the strain-rate when the yield-stress is exceeded.

## Artificial Thermal Ageing of Polyester Reinforced and - JoVE

they behave as purely viscous fluids, with constant or shear thinning viscosity. Viscoplastic fluids can present elasticity and thixotropy. Recently, an Oldroyd-B type constitutive equation was proposed by (de Souza Mendes, 2009) to model the behavior of elasto-viscoplastic fluids, and also thixotropy. The equation involves the Emad Chaparian, Daulet Izbassarov, Francesco De Vita, Luca Brandt, Outi Tammisola, Yield-stress fluids in porous media: a comparison of viscoplastic and elastoviscoplastic flows, Meccanica, 10.1007/s11012-019-01010-6, (2019). Yet, the velocity fields in the viscoplastic and elastoviscoplastic flows are comparable for small elastic effects.

A new elastoviscoplastic model based on the Herschel-Bulkley viscoplastic model. Journal of Non-Newtonian Fluid Mechanics, Elsevier, 2009, 158 (1-3), pp.154-161. �10.1016/j.jnnfm.2008.12.001�. �hal PDF | We present numerical simulations of laminar and turbulent channel flow of an elastoviscoplastic fluid. The non-Newtonian flow is simulated by | Find, read and cite all the research you A constitutive model for elasto-viscoplastic thixotropic materials is proposed.