Abstract (EN):
The numerical simulation of flows of very elastic fluids has been a subject
of intense research for the past decades with important industrial applications. Therefore,
it comes as no surprise that many efforts have been made to improve the convergence
capabilities of the numerical methods used. Recently, an important contribution to the
High Weissenberg Number Problem has been presented by Fattal and Kupferman [6], who
developed the matrix-logarithm of the conformation tensor technique, henceforth called
log-conformation tensor. This methodology guarantees that solutions of viscoelastic flow
problems are physically admissible and can deal with sharp elastic stress layers. Several
investigators have been using the log-conformation tensor and results for high Weissenberg
number flows have been reported. However, this technique has only been applied to simulate
confined flows of viscoelastic fluids. In this work we investigate the application of
the log-conformation tensor technique to three-dimensional unsteady free surface flows.
We applied the log-conformation tensor formulation to solve the Oldroyd-B constitutive
equation and solved the momentum equation using a finite difference Marker-and-Cell
type method. Results for the simulation of the extrudate swell of Oldroyd-B fluids at high
Weissenberg numbers are presented.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
20