Unsteady circular Couette flow of a Bingham plastic with the Augmented Lagrangian Method

Muravleva, L; Muravleva, E; Georgiou, GC; Mitsoulis, E

dc.contributor.author	Muravleva, L	en
dc.contributor.author	Muravleva, E	en
dc.contributor.author	Georgiou, GC	en
dc.contributor.author	Mitsoulis, E	en
dc.date.accessioned	2014-03-01T01:34:49Z
dc.date.available	2014-03-01T01:34:49Z
dc.date.issued	2010	en
dc.identifier.issn	0035-4511	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/20872
dc.subject	Augmented Lagrangian method	en
dc.subject	Bingham plastic	en
dc.subject	Circular Couette flow	en
dc.subject	Computer modeling	en
dc.subject	Couette viscometry	en
dc.subject	Unsteady flows	en
dc.subject	Uzawa method	en
dc.subject	Variational inequalities	en
dc.subject	Viscoplasticity	en
dc.subject	Yield surface	en
dc.subject.classification	Mechanics	en
dc.subject.other	POISEUILLE FLOWS	en
dc.subject.other	CESSATION	en
dc.subject.other	FLUIDS	en
dc.title	Unsteady circular Couette flow of a Bingham plastic with the Augmented Lagrangian Method	en
heal.type	journalArticle	en
heal.identifier.primary	10.1007/s00397-010-0497-y	en
heal.identifier.secondary	http://dx.doi.org/10.1007/s00397-010-0497-y	en
heal.language	English	en
heal.publicationDate	2010	en
heal.abstract	Numerical simulations are undertaken for unsteady flows of an ideal Bingham fluid in a circular Couette viscometer. The main difficulties in such simulations are caused by the non-differentiability of the constitutive equation and the need to determine the position and shape of the yield surface separating the yielded zones from the unyielded ones. In this work, these difficulties are overcome by using a numerical method based on variational inequalities, i. e. the augmented Lagrangian/Uzawa method. The start-up and cessation of circular Couette flows of a Bingham fluid are solved numerically assuming that only one of the cylinders is rotating. An improved theoretical upper bound for the stopping time in the case of cessation is derived. The numerical estimates for the stopping time compare well with the theoretical bounds. Moreover, with the adopted method the evolution of the velocity profiles and the locations of yielded/unyielded surfaces are accurately calculated. In flow cessation, we observe an interesting effect, namely the appearance of a small unyielded region adjoined to the outer cylinder shortly before cessation. © 2010 Springer-Verlag.	en
heal.publisher	SPRINGER	en
heal.journalName	Rheologica Acta	en
dc.identifier.doi	10.1007/s00397-010-0497-y	en
dc.identifier.isi	ISI:000284594800011	en
dc.identifier.volume	49	en
dc.identifier.issue	11	en
dc.identifier.spage	1197	en
dc.identifier.epage	1206	en