Abstract
It has been observed that when small oscillations are superposed on a steady shearing flow of a polymer fluid, the superposed dynamic viscosity becomes independent of the underlying steady shear rate at high frequencies of oscillation. Previous predictions of such behavior from the BKZ theory depended on the assumption that the linear shear modulus, G(t), can be continued analytically across the imaginary axis in the complex t-plane. It is shown that this cannot be done for a Doi-Edwards fluid and, therefore, that the previous arguments do not apply to this fluid. Nevertheless, a new derivation establishes that the observed high-frequency behavior of the superposed dynamic viscosity is, indeed, predicted by the Doi-Edwards fluid. An asymptotic expansion of the dynamic viscosity is also obtained.
Original language | English |
---|---|
Pages (from-to) | 299-308 |
Number of pages | 10 |
Journal | International Journal of Non-Linear Mechanics |
Volume | 27 |
Issue number | 2 |
DOIs | |
Publication status | Published - Mar 1992 |
Bibliographical note
Funding Information:Acknowledgement-We gratefully acknowledge the support given by The Flinders University of South Australia B. Bernstein as a Visiting Research Fellow in 1988, which made it possible to complete this work.