## Fluid Mechanics Seminar: Pierre Saramito

- Date: 04/07/2016

University of British Columbia

A Newton method for viscoplastic flows

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 $0<n<1$, 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.

**Bio**: Pierre Saramito completed his PhD at the Institut National Polytechnique de Grenoble in 1990 and his Habilitation at Université Joseph Fourier in 2002. Since 1994 he has been at the Centre national de la recherche scientifique (CNRS) first as a Chargé de Recherche and since 2009 as a Research Director.

Venue: ESB 2012