TY - JOUR
T1 - Compressive flow between parallel disks
T2 - II. oscillatory behavior of viscoelastic materials under a constant load
AU - Lee, S. J.
AU - Denn, M. M.
AU - Crochet, M. J.
AU - Metzner, A. B.
AU - Riggins, G. J.
N1 - Funding Information:
Financial support for this work was provided by the industrial sponsors of the Center for Composite Materials (Director: Professor R.B. Pipes). Dr. K.F. Wissbrun provided the majority of the rheological measurements.F .N. Cogswell, L.H. Keon and N. Sarkar arranged donations of the viscoelastic silicone polymer, the TLA and the PAA, respectively. We are grateful for all of this interest and support.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1984
Y1 - 1984
N2 - Compressive flow of viscoelastic materials between parallel disks under a constant load is studied analytically and experimentally. The key features of the unsteady deformation of viscoelastic materials are determined analytically using linear approximations to both the momentum and constitutive equations. In place of the monotonic "squeezing" found when Newtonian fluids are used, one finds in this case that oscillations arise when a critical value of a dimensionless group representing the ratio of elastic to inertial forces is exceeded. In order to study the process in detail, finite-element numerical calculations are used with the full equations for quantitative calculation of the oscillatory behavior of fluids described by contravariant convected Maxwell models; it is found that this calculation is in surprisingly close agreement with the linear approximation. Experimental measurements, utilizing three fluids of widely different properties, support the major predictions of the analysis. An important analytical conclusion arising from this study is that inertial terms can quite generally not be neglected, even for slow flows of viscous materials, in deformation processes starting from rest with a previously-un-deformed fluid. This observation is derived from the fact that in viscoelastic.
AB - Compressive flow of viscoelastic materials between parallel disks under a constant load is studied analytically and experimentally. The key features of the unsteady deformation of viscoelastic materials are determined analytically using linear approximations to both the momentum and constitutive equations. In place of the monotonic "squeezing" found when Newtonian fluids are used, one finds in this case that oscillations arise when a critical value of a dimensionless group representing the ratio of elastic to inertial forces is exceeded. In order to study the process in detail, finite-element numerical calculations are used with the full equations for quantitative calculation of the oscillatory behavior of fluids described by contravariant convected Maxwell models; it is found that this calculation is in surprisingly close agreement with the linear approximation. Experimental measurements, utilizing three fluids of widely different properties, support the major predictions of the analysis. An important analytical conclusion arising from this study is that inertial terms can quite generally not be neglected, even for slow flows of viscous materials, in deformation processes starting from rest with a previously-un-deformed fluid. This observation is derived from the fact that in viscoelastic.
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U2 - 10.1016/0377-0257(84)80050-6
DO - 10.1016/0377-0257(84)80050-6
M3 - Article
AN - SCOPUS:0021158254
SN - 0377-0257
VL - 14
SP - 301
EP - 325
JO - Journal of Non-Newtonian Fluid Mechanics
JF - Journal of Non-Newtonian Fluid Mechanics
IS - C
ER -