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Transport phenomena Ch.8 Polymeric liquid

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Presentation on theme: "Transport phenomena Ch.8 Polymeric liquid"— Presentation transcript:

1 Transport phenomena Ch.8 Polymeric liquid

2 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

3 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

4 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

5 Non-Newtonian Behaviors
4. Normal stress effect

6 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,

7 Constitutive model Elasticity Spring - dashpot : Maxwell model
: Relaxation time

8 Constitutive model Maxwell model : start-up shear flow, constant
Stationary shear flow : Newtonian (no shear thinning & normal stress)

9 Constitutive model Maxwell model : Oscillatory shear

10

11 Constitutive model Scalar equation to tensor equation ??? ???
1) Galilean invariance ??? ??? Total time derivative!

12 Constitutive model Scalar equation to tensor equation
1) Galilean invariance Total time derivative

13 Constitutive model Rotational invariance

14 Constitutive model Rotational invariance Position Velocity

15 Constitutive model Rotational invariance Velocity Shear rate?

16 Constitutive model Rotational invariance Velocity Shear rate?

17 Constitutive model Rotational invariance Transformation rule of tensor
Shear rate? Transformation rule of tensor Then, how about time derivative?


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