Inertially driven transient response in polymeric liquids

William W. Graessley, Scott Thomas Milner

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We report here a computational study, with inertial contributions included, of the time-dependent velocity and shear stress profiles following flow start-up from rest for a polymeric liquid. Earlier workers solved similar fluid-mechanical start-up problems with viscoelastic character represented by a single Maxwell element. They found significant oscillatory departures from the steady-state velocity profile that persist throughout the entire period of stress growth to steady state. Such results are unsettling since they imply that the usual assumptions about velocity fields for transient tests of polymeric liquids are seriously in error. It turns out, however, that such oscillations are rapidly suppressed when a broad distribution of relaxation times is employed, the physically appropriate situation for polymeric liquids. The initial shear wave oscillations decay quickly compared with the time to reach the stress steady state when realistic descriptions of their viscoelastic character are employed. We note that a combination of inertial contributions with sparse relaxation spectra in fluid-mechanical modeling can lead to spurious velocity and stress field predictions for polymeric liquid flows.

Original languageEnglish (US)
Pages (from-to)26-33
Number of pages8
JournalJournal of Non-Newtonian Fluid Mechanics
Volume159
Issue number1-3
DOIs
StatePublished - Jun 1 2009

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Transient Response
transient response
Transient analysis
velocity distribution
Start-up
Liquid
Velocity Field
Liquids
liquids
Oscillation
Fluid
oscillations
Liquid Flow
fluids
liquid flow
Velocity Profile
Stress Field
Shear Stress
Relaxation Time
shear stress

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering
  • Applied Mathematics

Cite this

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Inertially driven transient response in polymeric liquids. / Graessley, William W.; Milner, Scott Thomas.

In: Journal of Non-Newtonian Fluid Mechanics, Vol. 159, No. 1-3, 01.06.2009, p. 26-33.

Research output: Contribution to journalArticle

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AU - Graessley, William W.

AU - Milner, Scott Thomas

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