Abstract

MARTINS, R. R.; SILVEIRA, F. S.  and  MARTINS-COSTA, M. L.. Numerical investigation of inertia and shear-thinning effects in axisymmetric flows of carreau fluids by a galerkin least-squares method. Lat. Am. appl. res. [online]. 2008, vol.38, n.4, pp.321-328. ISSN 0327-0793.

This article presents a finite element simulation of Carreau flows through an abrupt contraction. The employed mechanical model consists in using the Carreau viscosity equation to characterize the shear-thinning fluid behavior, giving rise to a generalization of Navier-Stokes equation containing a non-linear diffusion term. A Galerkin-Least Squares methodology approximates the mechanical model circumventing the Babuška-Brezzi condition, which consists of adding to the classical Galerkin method mesh-dependent residuals, resulting from least squares of the Euler-Lagrange equations. Numerical results for both velocity and pressure fields accounting for shear-thinning and fluid inertia effects have been obtained for an axisymmetric 4:1 sudden contraction with Carreau number ranging from 0 to 100, power-law exponent from 0.2 to 1.0 and Reynolds number from 2 to 100. These results have shown good agreement with the literature.

Keywords : Non-Newtonian Fluids; Carreau Equation; Sudden Contraction Flow; Galerkin-Least Squares Method.

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