First normal stress difference of entangled polymer solutions in large amplitude oscillatory shear flow

2010 ◽  
Vol 54 (6) ◽  
pp. 1243-1266 ◽  
Author(s):  
Jung Gun Nam ◽  
Kyung Hyun Ahn ◽  
Seung Jong Lee ◽  
Kyu Hyun
Keyword(s):  
Shear Flow ◽  
Normal Stress ◽  
Large Amplitude ◽  
Normal Stress Difference ◽  
Stress Difference ◽  
Large Amplitude Oscillatory Shear ◽  
First Normal Stress Difference ◽  
Oscillatory Shear Flow ◽  
Entangled Polymer ◽  
Entangled Polymer Solutions

The first normal stress difference of non-Brownian hard-sphere suspensions in the oscillatory shear flow near the liquid and crystal coexistence region

Soft Matter ◽  
2020 ◽  
Vol 16 (43) ◽  
pp. 9864-9875
Author(s):  
Young Ki Lee ◽  
Kyu Hyun ◽  
Kyung Hyun Ahn
Keyword(s):  
Shear Flow ◽  
Normal Stress ◽  
Hard Sphere ◽  
Normal Stress Difference ◽  
Oscillatory Shear ◽  
Stress Difference ◽  
Large Amplitude Oscillatory Shear ◽  
First Normal Stress Difference ◽  
Oscillatory Shear Flow ◽  
Sphere Suspensions

The first normal stress difference (N1) as well as shear stress of non-Brownian hard-sphere suspensions in small to large amplitude oscillatory shear flow is investigated.

Normal Stress Differences of Human Blood in Unidirectional Large-Amplitude Oscillatory Shear Flow

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Chaimongkol Saengow ◽  
Alan Jeffrey Giacomin ◽  
Andrea Stephanie Dimitrov
Keyword(s):  
Shear Flow ◽  
Normal Stress ◽  
Human Blood ◽  
Stress Responses ◽  
Large Amplitude ◽  
Normal Stress Difference ◽  
Stress Difference ◽  
Large Amplitude Oscillatory Shear ◽  
Oscillatory Shear Flow ◽  
Normal Stress Differences

Abstract This work analyzes normal stress difference responses in blood tested in unidirectional large-amplitude oscillatory shear flow (udLAOS), a novel rheological test, designed for human blood. udLAOS mimics the pulsatile flow in veins and arteries, in the sense that it never reverses, and yet also nearly stops once per heartbeat. As for our continuum fluid model, we choose the Oldroyd 8-constant framework for its rich diversity of popular constitutive equations, including the corotational Jeffreys fluid. This work arrives at exact solutions for normal stress differences from the corotational Jeffreys fluid in udLAOS. We discover fractional harmonics comprising the transient part of the normal stress difference responses, and both integer and fractional harmonics, the alternant part. By fractional, we mean that these occur at frequencies other than integer multiples of the superposed oscillation frequency. More generally, predictions from the Oldroyd 8-constant framework are explored by means of the finite difference method. Finally, the generalized versions of both the Oldroyd 8-constant framework and the corotational Jeffreys fluid are employed to predict the nonlinear normal stress responses for the model parameters fitted to udLAOS measurements from three very different donors, all healthy. From our predictions, we are led to expect less variation in normal stress differences in udLAOS from healthy donor to donor, than for the corresponding measured shear stress responses.

scholarly journals Vliv smykové viskozity a elasticity na senzorickou viskozitu modelových kapalných potravin

1999 ◽  
Vol 17 (No. 1) ◽  
pp. 23-30 ◽  
Author(s):  
P. Novotna ◽  
M. Houska ◽  
V. Sopr ◽  
H. Valentova ◽  
P. Stern
Keyword(s):  
Shear Flow ◽  
Normal Stress ◽  
Shear Viscosity ◽  
Normal Stress Difference ◽  
Rheological Parameters ◽  
Cellulose Derivatives ◽  
Moderate Increase ◽  
Stress Difference ◽  
First Normal Stress Difference ◽  
Normal Difference

The shear flow rheological properties of sugar solutions (70% w/w concentration) modified by different cellulose derivatives have been measured. Thickeners  were expected to cause the viscoelastic behaviour of the resulting sol ution. Therefore, the elastic rheological parameters were measured by oscillatory shear technique (phase angle, elastic modulus) and also the first normal stress difference N<sub>1</sub>. The increase of thickener concen tration caused a moderate increase of non-Newtonian behaviour in the shear flow. The sensory viscosity (ra nged between 0 and 100%) was evaluated by five different methods - as an effort for stirring with teaspoon, time for flowing down the spoon, slurping from spoon, compression between tongue and palate and swallowing. The influence of shear viscosity and first normal difference on sensory viscosity was tested. Correlation procedu re between change of sensory viscosity .tlSE and change of shear viscosity .tlJ.Iz showed that only for swallowing there is a statistically evident de­pendence. The correlation between change of sensory viscosity t.SE and first normal stress difference N<sub>1</sub> is not statistically   evident. For all the methods of sensory evaluation the dependence between these parameters is only weak and indirect (with increasing normal stress difference the sensory viscosity is decreasing).

Numerical Simulation of a First Normal Stress Difference-Based Model for Shear-Induced Crystallization of Polyethylene

2011 ◽  
Vol 266 ◽  
pp. 130-134
Author(s):  
Jin Yan Wang ◽  
Jing Bo Chen ◽  
Chang Yu Shen
Keyword(s):  
Numerical Simulation ◽  
Shear Flow ◽  
Normal Stress ◽  
Viscoelastic Model ◽  
Normal Stress Difference ◽  
Simple Shear Flow ◽  
Stress Difference ◽  
Avrami Model ◽  
First Normal Stress Difference ◽  
Induced Crystallization

The paper presents a numerical simulation for the isothermal flow-induced crystallization of polyethylene under a simple shear flow. The effect of flow on crystllization is considered through the simple mathematical relationship between the additional number of nuclei induced by shear treatment and the first normal stress difference. Leonov viscoelastic model and Avrami model are used to describe the normal stress difference and the crystallization kinetics, respectively. It is found that the short-term shear treatment has a large effect on the crystallization dynamics of polyethylene , but the effect of the intensity of the shear flow is not infinite ,which shows a saturation phenomenon, namely, the accelerated degree of crystallization tending to level off when the shear rate or shear time is large enough.

scholarly journals Padé approximant for normal stress differences in large-amplitude oscillatory shear flow

2018 ◽  
Vol 30 (4) ◽  
pp. 040910 ◽  
Author(s):  
P. Poungthong ◽  
C. Saengow ◽  
A. J. Giacomin ◽  
C. Kolitawong ◽  
D. Merger ◽  
...  
Keyword(s):  
Shear Flow ◽  
Normal Stress ◽  
Large Amplitude ◽  
Padé Approximant ◽  
Oscillatory Shear ◽  
Large Amplitude Oscillatory Shear ◽  
Pade Approximant ◽  
Oscillatory Shear Flow ◽  
Normal Stress Differences
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