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ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
Stabilized Galerkin least-square approximations for shear-thinning viscosity and relaxation time White-Metzner-like viscoelastic fluid flow
Submission Author:
Natan Alexandre de Oliveira , RS , Brazil
Co-Authors:
Natan Alexandre de Oliveira, Vitor Dal Bo Abella, Sergio Frey
Presenter: Natan Alexandre de Oliveira
doi://10.26678/ABCM.ENCIT2020.CIT20-0527
Abstract
Despite the presence of viscoelastic fluid in Nature, the importance of this class of fluids in industrial applications and then that, the knowledge of the behavior of this materials under rheological and kinematics influence is the focus of interest in the past 300 years since Newton’s first understanding of rheological characteristics, as viscosity. In the present work, the flow of a non-linear pseudoplastic viscoelastic fluid is given by the extended White-Metzner constitutive equation and the non-linear terms given by a Carreau-Yasuda–like model for viscosity and relaxation time. The solution to this problem is approximated by the coupled Petrov-Galerkin and stabilized Galerkin least-square variational formulation in terms of velocity, extra-stress and additive constant and the non-linear system solved by the Newton method via low- and equal-order finite Lagrangian finite elements. A simple flow is considered a problem domain to evaluate the influence of rheological parameters without kinematical interference. The preliminary results point to a fine agreement between analytical and approximate solutions for the constant viscosity and relaxation time case. Shows the influence of the shear-thinning viscosity and relaxation time in the longitudinal velocity. Also shows an important dependence of the shear-thinning relaxation time in both first normal and shear stress.
Keywords
GLS, non-linear, shear-thinning, Viscoelastic, White-Metzner
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