A Newton method for viscoplastic flows

Fluids Seminar
April 7, 2016 11:00 pm

Speaker:  Pierre Saramito, CNRS

URL for Speaker:  http://www-ljk.imag.fr/membres/Pierre.Saramito/

Location:  ESB 2012

Intended Audience:  Public

For the first time, a Newton method is proposed for the unregularized viscoplastic fluid flow problem. It leads to a quadratic convergence for Herschel-Bulkley fluids when n is strictly between zero and one, where n is the power law index. Performances are enhanced by using the inexact variant of the Newton method and, for solving the Jacobian system, by using an efficient preconditioner based on the regularized problem. A demonstration is provided by computing a viscoplastic flow in a pipe with a square cross section. Comparisons with the augmented Lagrangian algorithm show a dramatic reduction of the required computing time while this new algorithm provides an equivalent accuracy for the prediction of the yield surfaces.