Effect of flow kinematics on extensional viscosity of dilute polymer solutions

Fuente: arXiv
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Main Authors: Koide, Yusuke, Ishida, Takato, Uneyama, Takashi, Masubuchi, Yuichi
Format: Preprint
Published: 2026
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author Koide, Yusuke
Ishida, Takato
Uneyama, Takashi
Masubuchi, Yuichi
author_facet Koide, Yusuke
Ishida, Takato
Uneyama, Takashi
Masubuchi, Yuichi
contents We investigate the effect of flow kinematics on the extensional viscosity of dilute polymer solutions by conducting dissipative particle dynamics simulations under uniaxial, planar, and biaxial extensional flows. At high extension rates, dilute polymer solutions exhibit strain hardening under these flows, while the quantitative behavior depends on the flow type. To elucidate the physical origin of this flow-kinematics dependence, we relate the extensional viscosity to polymer conformation using an analytical expression derived from a single-chain model. The resulting relation allows us to separate the contribution of flow-induced polymer conformational changes and the purely kinematic contribution determined by the structure of the velocity gradient tensor. When polymers remain almost unperturbed by extensional flows, differences in the extensional viscosity are governed primarily by the purely kinematic effects. In contrast, as polymers are stretched, the gyration radius in the extensional direction becomes the dominant factor, and differences in the stretching degree in this direction lead to corresponding variations in the extensional viscosity.
format Preprint
id arxiv_https___arxiv_org_abs_2603_11518
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Effect of flow kinematics on extensional viscosity of dilute polymer solutions
Koide, Yusuke
Ishida, Takato
Uneyama, Takashi
Masubuchi, Yuichi
Soft Condensed Matter
We investigate the effect of flow kinematics on the extensional viscosity of dilute polymer solutions by conducting dissipative particle dynamics simulations under uniaxial, planar, and biaxial extensional flows. At high extension rates, dilute polymer solutions exhibit strain hardening under these flows, while the quantitative behavior depends on the flow type. To elucidate the physical origin of this flow-kinematics dependence, we relate the extensional viscosity to polymer conformation using an analytical expression derived from a single-chain model. The resulting relation allows us to separate the contribution of flow-induced polymer conformational changes and the purely kinematic contribution determined by the structure of the velocity gradient tensor. When polymers remain almost unperturbed by extensional flows, differences in the extensional viscosity are governed primarily by the purely kinematic effects. In contrast, as polymers are stretched, the gyration radius in the extensional direction becomes the dominant factor, and differences in the stretching degree in this direction lead to corresponding variations in the extensional viscosity.
title Effect of flow kinematics on extensional viscosity of dilute polymer solutions
topic Soft Condensed Matter
url https://arxiv.org/abs/2603.11518