Non-linear stress response of non-gap-spanning magnetic chains suspended in a Newtonian fluid under oscillatory shear test: A direct numerical simulation

M R Hashemi, M T Manzari, R Fatehi

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Abstract

A direct numerical simulation approach is used to investigate the effective non-linear viscoelastic stress response of non-gap-spanning magnetic chains suspended in a Newtonian fluid. The suspension is confined in a channel and the suspended clusters are formed under the influence of a constant external magnetic field. Large amplitude oscillatory shear (LAOS) tests are conducted to study the non-linear rheology of the system. The effect of inertia on the intensity of non-linearities is discussed for both magnetic and non-magnetic cases. By conducting magnetic sweep tests, the intensity and quality of the non-linear stress response are studied as a function of the strength of the external magnetic field. The Chebyshev expansion of the stress response is used to quantify the non-linear intra-cycle behaviour of the suspension. It is demonstrated that the system shows a strain-softening behaviour while the variation of the dynamic viscosity is highly sensitive to the external magnetic field. In a series of strain sweep tests, the overall non-linear viscoelastic behaviour of the system is also investigated for both a constant frequency and a constant strain-rate amplitude. It is shown that the intra-cycle behaviour of the system is different from its inter-cycle behaviour under LAOS tests.
Original languageEnglish
Article number107106
JournalPhysics of Fluids
Volume29
Issue number10
DOIs
Publication statusPublished - Oct 2017

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Newtonian fluids
direct numerical simulation
shear
cycles
magnetic fields
rheology
inertia
plastic deformation
strain rate
nonlinearity
viscosity
conduction
expansion

Cite this

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title = "Non-linear stress response of non-gap-spanning magnetic chains suspended in a Newtonian fluid under oscillatory shear test: A direct numerical simulation",
abstract = "A direct numerical simulation approach is used to investigate the effective non-linear viscoelastic stress response of non-gap-spanning magnetic chains suspended in a Newtonian fluid. The suspension is confined in a channel and the suspended clusters are formed under the influence of a constant external magnetic field. Large amplitude oscillatory shear (LAOS) tests are conducted to study the non-linear rheology of the system. The effect of inertia on the intensity of non-linearities is discussed for both magnetic and non-magnetic cases. By conducting magnetic sweep tests, the intensity and quality of the non-linear stress response are studied as a function of the strength of the external magnetic field. The Chebyshev expansion of the stress response is used to quantify the non-linear intra-cycle behaviour of the suspension. It is demonstrated that the system shows a strain-softening behaviour while the variation of the dynamic viscosity is highly sensitive to the external magnetic field. In a series of strain sweep tests, the overall non-linear viscoelastic behaviour of the system is also investigated for both a constant frequency and a constant strain-rate amplitude. It is shown that the intra-cycle behaviour of the system is different from its inter-cycle behaviour under LAOS tests.",
author = "Hashemi, {M R} and Manzari, {M T} and R Fatehi",
note = "The corresponding author wishes to express his sincerest thanks to the Iran National Science Foundation (INSF) for supporting this work under Contract Number 92021291.",
year = "2017",
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language = "English",
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TY - JOUR

T1 - Non-linear stress response of non-gap-spanning magnetic chains suspended in a Newtonian fluid under oscillatory shear test

T2 - A direct numerical simulation

AU - Hashemi, M R

AU - Manzari, M T

AU - Fatehi, R

N1 - The corresponding author wishes to express his sincerest thanks to the Iran National Science Foundation (INSF) for supporting this work under Contract Number 92021291.

PY - 2017/10

Y1 - 2017/10

N2 - A direct numerical simulation approach is used to investigate the effective non-linear viscoelastic stress response of non-gap-spanning magnetic chains suspended in a Newtonian fluid. The suspension is confined in a channel and the suspended clusters are formed under the influence of a constant external magnetic field. Large amplitude oscillatory shear (LAOS) tests are conducted to study the non-linear rheology of the system. The effect of inertia on the intensity of non-linearities is discussed for both magnetic and non-magnetic cases. By conducting magnetic sweep tests, the intensity and quality of the non-linear stress response are studied as a function of the strength of the external magnetic field. The Chebyshev expansion of the stress response is used to quantify the non-linear intra-cycle behaviour of the suspension. It is demonstrated that the system shows a strain-softening behaviour while the variation of the dynamic viscosity is highly sensitive to the external magnetic field. In a series of strain sweep tests, the overall non-linear viscoelastic behaviour of the system is also investigated for both a constant frequency and a constant strain-rate amplitude. It is shown that the intra-cycle behaviour of the system is different from its inter-cycle behaviour under LAOS tests.

AB - A direct numerical simulation approach is used to investigate the effective non-linear viscoelastic stress response of non-gap-spanning magnetic chains suspended in a Newtonian fluid. The suspension is confined in a channel and the suspended clusters are formed under the influence of a constant external magnetic field. Large amplitude oscillatory shear (LAOS) tests are conducted to study the non-linear rheology of the system. The effect of inertia on the intensity of non-linearities is discussed for both magnetic and non-magnetic cases. By conducting magnetic sweep tests, the intensity and quality of the non-linear stress response are studied as a function of the strength of the external magnetic field. The Chebyshev expansion of the stress response is used to quantify the non-linear intra-cycle behaviour of the suspension. It is demonstrated that the system shows a strain-softening behaviour while the variation of the dynamic viscosity is highly sensitive to the external magnetic field. In a series of strain sweep tests, the overall non-linear viscoelastic behaviour of the system is also investigated for both a constant frequency and a constant strain-rate amplitude. It is shown that the intra-cycle behaviour of the system is different from its inter-cycle behaviour under LAOS tests.

U2 - 10.1063/1.5009360

DO - 10.1063/1.5009360

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VL - 29

JO - Physics of Fluids

JF - Physics of Fluids

SN - 1070-6631

IS - 10

M1 - 107106

ER -