Free (open) boundary condition: Some experiences with viscous flow simulations

Mitsoulis, E; Malamataris, NA

dc.contributor.author	Mitsoulis, E	en
dc.contributor.author	Malamataris, NA	en
dc.date.accessioned	2014-03-01T02:09:15Z
dc.date.available	2014-03-01T02:09:15Z
dc.date.issued	2012	en
dc.identifier.issn	02712091	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29781
dc.subject	Compressibility	en
dc.subject	Free (open) boundary condition (FBC, OBC)	en
dc.subject	Gravity	en
dc.subject	Inertia	en
dc.subject	Newtonian fluid	en
dc.subject	Pressure dependence of viscosity	en
dc.subject	Surface tension	en
dc.subject	Viscous flow	en
dc.subject	Wall slip	en
dc.subject.other	Axisymmetric	en
dc.subject.other	Bench-mark problems	en
dc.subject.other	Computational aspects	en
dc.subject.other	Free (open) boundary condition (FBC, OBC)	en
dc.subject.other	Inertia	en
dc.subject.other	International journals	en
dc.subject.other	Newton-Raphson	en
dc.subject.other	Newtonian fluids	en
dc.subject.other	Nonisothermal	en
dc.subject.other	Numerical results	en
dc.subject.other	Outflow condition	en
dc.subject.other	Pressure dependence	en
dc.subject.other	Steady-state condition	en
dc.subject.other	Wall slip	en
dc.subject.other	Compressibility	en
dc.subject.other	Fluid mechanics	en
dc.subject.other	Gravitation	en
dc.subject.other	Surface tension	en
dc.subject.other	Viscous flow	en
dc.subject.other	Boundary conditions	en
dc.title	Free (open) boundary condition: Some experiences with viscous flow simulations	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/fld.2608	en
heal.identifier.secondary	http://dx.doi.org/10.1002/fld.2608	en
heal.publicationDate	2012	en
heal.abstract	The free (or open) boundary condition (FBC, OBC) was proposed by Papanastasiou et al. (A new outflow boundary condition, International Journal for Numerical Methods in Fluids, 1992; 14:587-608) to handle truncated domains with synthetic boundaries where the outflow conditions are unknown. In the present work, implementation of the FBC has been tested in several benchmark problems of viscous flow in fluid mechanics. The FEM is used to provide numerical results for both cases of planar and axisymmetric domains under laminar, isothermal or non-isothermal, steady-state conditions, for Newtonian fluids. The effects of inertia, gravity, compressibility, pressure dependence of the viscosity, slip at the wall, and surface tension are all considered individually in the extrudate-swell benchmark problem for a wide range of the relevant parameters. The present results extend previous ones regarding the applicability of the FBC and show cases where the FBC is inappropriate, namely in the extrudate-swell problem with gravity or surface-tension effects. Particular emphasis has been given to the pressure at the outflow, which is the most sensitive quantity of the computations. In all cases where FBC is appropriate, excellent agreement has been found in comparisons with results from very long domains. The formulation for Picard-type iterations is given in some detail, and the differences with the Newton-Raphson formulation are highlighted regarding some computational aspects. © 2011 John Wiley & Sons, Ltd.	en
heal.journalName	International Journal for Numerical Methods in Fluids	en
dc.identifier.doi	10.1002/fld.2608	en
dc.identifier.volume	68	en
dc.identifier.issue	10	en
dc.identifier.spage	1299	en
dc.identifier.epage	1323	en