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Transport phenomena Ch.8 Polymeric liquid
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Non-Newtonian Behaviors
1. Shear thinning & thickening : Nonlinear relation between shear rate & stress Viscosity depending on shear rate Shear thinning Newtonian Shear thickening Interaction between flow & structure
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Non-Newtonian Behaviors
2. Elasticity : Solid like response to deformation Elastic solid Viscous liquid Force Force Viscoelastic fluid : Force Oscillatory shear When Ex) Water Storage modulus Loss modulus
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Non-Newtonian Behaviors
3. Yield stress(Bingham plastic fluid) : Behaves as a rigid body at low stresses but flows as a viscous fluid at high stress (ex. Toothpaste, Mayonnaise) Planar pressure driven flow yield stress
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Non-Newtonian Behaviors
4. Normal stress effect
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Constitutive model Shear thinning & thickening
Generalized Newtonian fluid - Power law viscosity : Shear thinning ! Infinite viscosity for - Carreau model Planar pressure driven flow, power law fluid For , By symmetry,
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Constitutive model Elasticity Spring - dashpot : Maxwell model
: Relaxation time
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Constitutive model Maxwell model : start-up shear flow, constant
Stationary shear flow : Newtonian (no shear thinning & normal stress)
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Constitutive model Maxwell model : Oscillatory shear
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Constitutive model Scalar equation to tensor equation ??? ???
1) Galilean invariance ??? ??? Total time derivative!
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Constitutive model Scalar equation to tensor equation
1) Galilean invariance Total time derivative
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Constitutive model Rotational invariance
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Constitutive model Rotational invariance Position Velocity
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Constitutive model Rotational invariance Velocity Shear rate?
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Constitutive model Rotational invariance Velocity Shear rate?
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Constitutive model Rotational invariance Transformation rule of tensor
Shear rate? Transformation rule of tensor Then, how about time derivative?
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