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Author(s): Vera Ribeiro
P. M. Coelho
F. T. Pinho
M. A. Alves
Title: Three dimensional effects of Newtonian and viscoelastic fluids past a confined cylinder
Issue Date: 2011
Abstract: The 2D laminar flow around a confined cylinderwith a 50% blockage ratio is an establishedbenchmark in the development of numericalmethods for non-Newtonian fluids [1]. Its practicalapplication is accompanied by 3D flowcharacteristics and the combination of flow inertia,viscoelasticity and three-dimensionality leads tounexpected results. As such, the impact of 3Deffects depends essentially on the aspect ratio ofthe cylinder, the type of confinement, theReynolds number and also on the rheology of theworking fluid.The study of viscoelastic flow past a confinedcylinder in a rectangular duct with a blockage ratioof 50% shows the appearance of 3D effects nearthe end walls [2]. Studies of the flow past gradualcontractions, which can be qualitatively comparedwith the upstream flow around a cylinder, showthe appearance of velocity overshoots near theend walls upstream the contraction. This velocityovershoots, called cats ears phenomenon isdue to elastic effects [3, 4].Most of the experimental studies of viscoelasticfluid flow past a confined cylinder refer to steadycreeping flow conditions or, in contrast, to highReynolds number flows, close or above the onsetof vortex shedding. So, the lack of experimentalstudies that consider flow around a cylinder fromcreeping conditions up the onset of laminar vortexshedding is one of the motivations of this work.The existence of 3D effects and their dependencywith the aspect ratio is also an important aspect ofour investigation. The main goal of this study is toinvestigate the flows of a Newtonian fluid and aviscoelastic shear-thinning fluid past a confinedcylinder from creeping flow conditions (Re 0)up to the critical condition for the onset of vortexshedding. The Newtonian results obtained arecompared with numerical calculations, using anin-house finite volume code [5].
Subject: Outras ciências da engenharia e tecnologias
Other engineering and technologies
Scientific areas: Ciências da engenharia e tecnologias::Outras ciências da engenharia e tecnologias
Engineering and technology::Other engineering and technologies
Source: IBEREO 2011 Meeting
Document Type: Artigo em Livro de Atas de Conferência Internacional
Rights: restrictedAccess
Appears in Collections:FEUP - Artigo em Livro de Atas de Conferência Internacional

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