Numerical simulation of the flow and heat transfer around a cylinder with a pulsating approaching flow at a low Reynolds number

Papadakis, G; Bergeles, G

dc.contributor.author	Papadakis, G	en
dc.contributor.author	Bergeles, G	en
dc.date.accessioned	2014-03-01T01:16:49Z
dc.date.available	2014-03-01T01:16:49Z
dc.date.issued	2001	en
dc.identifier.issn	0954-4062	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/14243
dc.subject	Computational fluid dynamics	en
dc.subject	Cylinder in cross-flow	en
dc.subject	Flow pulsation	en
dc.subject	Heat transfer	en
dc.subject	Lock-on	en
dc.subject.classification	Engineering, Mechanical	en
dc.subject.other	Computer simulation	en
dc.subject.other	Cylinders (shapes)	en
dc.subject.other	Heat transfer	en
dc.subject.other	Nusselt number	en
dc.subject.other	Pulsatile flow	en
dc.subject.other	Reynolds number	en
dc.subject.other	Vortex flow	en
dc.subject.other	Flow pulsation	en
dc.subject.other	Lock-on regions	en
dc.subject.other	Computational fluid dynamics	en
dc.title	Numerical simulation of the flow and heat transfer around a cylinder with a pulsating approaching flow at a low Reynolds number	en
heal.type	journalArticle	en
heal.identifier.primary	10.1243/0954406011520463	en
heal.identifier.secondary	http://dx.doi.org/10.1243/0954406011520463	en
heal.language	English	en
heal.publicationDate	2001	en
heal.abstract	Two-dimensional numerical simulations of flow and heat transfer around a cylinder at a Reynolds number Re = 100 have been performed in order to investigate the effect of imposed inlet velocity pulsation on the heat transfer and flow fields. First the code is validated against existing results from the literature and then several external frequencies are examined. The numerical results confirm the existence of a vortex shedding lock-on regime where the wake behaves in a very ordered manner (completely periodic). Outside the lock-on region the flow is quasiperiodic. The length and centre of the mean recirculating zone downstream of the cylinder are also affected by the external pulsation. Regarding heat transfer, the results indicate that by imposing an external velocity pulsation, the root mean square (r.m.s.) of the local Nusselt number Nu increases, but the mean value increases only in the area downstream of the separation point. The mechanism responsible for this is identified: hot fluid is engulfed by stronger vortices (compared with the steady approaching flow case) shed from the upper and lower side of the cylinder and returned close to the downstream stagnation point. This mechanism also explains the observed variation in Nu with time. In the front part of the cylinder, the Nu varies almost sinusoidally and closely follows the imposed external velocity pulsation. The results indicate also that there is a range of external frequencies where the time and spatially averaged Nu number is maximized.	en
heal.publisher	PROFESSIONAL ENGINEERING PUBLISHING LTD	en
heal.journalName	Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science	en
dc.identifier.doi	10.1243/0954406011520463	en
dc.identifier.isi	ISI:000168967100010	en
dc.identifier.volume	215	en
dc.identifier.issue	1	en
dc.identifier.spage	105	en
dc.identifier.epage	119	en