Unsteady flow field in a square tube T-junction

Anagnostopoulos, JS; Mathioulakis, DS

dc.contributor.author	Anagnostopoulos, JS	en
dc.contributor.author	Mathioulakis, DS	en
dc.date.accessioned	2014-03-01T01:54:04Z
dc.date.available	2014-03-01T01:54:04Z
dc.date.issued	2004	en
dc.identifier.issn	1070-6631	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/27180
dc.subject.classification	Mechanics	en
dc.subject.classification	Physics, Fluids & Plasmas	en
dc.subject.other	CAROTID-ARTERY BIFURCATION	en
dc.subject.other	CURVED PIPE	en
dc.subject.other	SEPARATION	en
dc.subject.other	ATHEROSCLEROSIS	en
dc.subject.other	STRESS	en
dc.subject.other	MODEL	en
dc.subject.other	FLUID	en
dc.title	Unsteady flow field in a square tube T-junction	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	2004	en
heal.abstract	This work constitutes an extension of two previous experimental studies, examining the flow field in a square tube T-junction with a time-dependent periodic inlet flow rate (zero to a maximum value) and equal branch flow rates. Based on numerical predictions, more details of the flow field are revealed, not being easily detectable by the experiment. Emphasis is given on the recirculation regions examining the velocity, pressure, and wall shear stress distributions as well as the limiting streamlines as a function of time. During acceleration an adverse pressure gradient builds up at the junction due to the streamlines curvature, causing flow separation before flow peak, which initiates at the corners of the tube cross section. Flow separation and reattachment lines, determined by the limiting streamline topology, move apart during deceleration. Streamwise cross-flow vortices appear in both branches, being much stronger in the 90degrees branch. The characteristics of the latter vortices, namely their circulation, swirl ratio, velocity distribution, as well as the process of their birth at the beginning of each cycle are examined in detail. Wall shear stress distributions exhibit maximum values at the entrance of the 90degrees branch, taking values proportional to the inlet time-dependent flow rate. Finally, comparisons with steady inlet conditions showed that in the unsteady case the flow can sustain much higher adverse pressure gradients before separating. (C) 2004 American Institute of Physics.	en
heal.publisher	AMER INST PHYSICS	en
heal.journalName	PHYSICS OF FLUIDS	en
dc.identifier.isi	ISI:000224456800010	en
dc.identifier.volume	16	en
dc.identifier.issue	11	en
dc.identifier.spage	3900	en
dc.identifier.epage	3910	en