Doctoral Thesis
DOI
https://doi.org/10.11606/T.55.2017.tde-16012017-162912
Document
Author
Full name
Juliana Bertoco
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2016
Supervisor
Committee
Tomé, Murilo Francisco (President)
Carvalho, Márcio da Silveira
Paulo, Gilcilene Sanchez de
Seleghim Junior, Paulo
Souza, Leandro Franco de
Title in Portuguese
Solução numérica do modelo constitutivo KBKZ-PSM para escoamentos com superfícies livres
Keywords in Portuguese
Campos de deformação
Diferenças finitas
Equação constitutiva integral
KBKZ-PSM
Superfícies livres
Abstract in Portuguese
Title in English
Numerical solution of the KBKZ-PSM constitutive model for flows with free surfaces
Keywords in English
Deformation fields
Finite difference
Free surface
Integral constitutive equation
KBKZ-PSM
Abstract in English
Unsteady viscoelastic free surface flows are common in many industrial processes and a variety of numerical techniques have been employed to simulate these flows. The majority of constitutive models employed are based on differential equations to define the extra stress tensor. However, for some complex fluids, for instance, Boger fluids, integral models are more adequate to approximate the nonlinear behaviour of these fluids. This work deals with the numerical solution of the integral constitutive model KBKZ-PSM for two-dimensional unsteady free surface flows. The proposed numerical method is a numerical technique that employs finite differences to simulate moving free surface flows that interact with solid walls. The main features of the method are: numerical solution of the momentum and mass equations by an implicit method; the pressure condition on the free surface is implicitly coupled with the Poisson equation for obtaining the pressure field from mass conservation; a novel scheme for defining the past times t is employed; the Finger tensor is calculated by the deformation fields method and is advanced in time by the modified Euler method. This new technique is verified by solving shear and uniaxial elongational flows. Moreover, an analytic solution for channel flows is obtained that is used in the verification and convergence analysis of the proposed methodology. For free surface flows, the assessment of convergence lies on the mesh refinement on the simulation of a jet impinging on a flat surface and the extrudade swell problem. Finally, the new method is applied to investigate the jet buckling phenomenon and extrudate swell of KBKZ-PSM fluids.

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Publishing Date
2017-01-16

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