Computational study of flow resonances and forces on a cylinder vibrating in-line to a steady flow

Kaiktsis, L; Triantafyllou, GS

dc.contributor.author	Kaiktsis, L	en
dc.contributor.author	Triantafyllou, GS	en
dc.date.accessioned	2014-03-01T02:52:37Z
dc.date.available	2014-03-01T02:52:37Z
dc.date.issued	2010	en
dc.identifier.issn	0277027X	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/35959
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-80155180576&partnerID=40&md5=e2af73d9fc34e708883360f00a35995a	en
dc.subject	In-line oscillation	en
dc.subject	Spectral element method	en
dc.subject	Vortex-induced vibrations	en
dc.subject.other	Chaotic flows	en
dc.subject.other	Computational results	en
dc.subject.other	Computational studies	en
dc.subject.other	Computed flows	en
dc.subject.other	Cylinder diameters	en
dc.subject.other	Cylinder oscillations	en
dc.subject.other	Excitation frequency	en
dc.subject.other	Flow dynamics	en
dc.subject.other	Flow resonance	en
dc.subject.other	Higher harmonics	en
dc.subject.other	In-line	en
dc.subject.other	In-line oscillations	en
dc.subject.other	Oscillation amplitude	en
dc.subject.other	Oscillation frequency	en
dc.subject.other	Spectral element method	en
dc.subject.other	Strouhal frequencies	en
dc.subject.other	Subharmonics	en
dc.subject.other	Two-dimensional flow	en
dc.subject.other	Vortex induced vibration	en
dc.subject.other	Vortex pattern	en
dc.subject.other	Vortex street	en
dc.subject.other	Circular cylinders	en
dc.subject.other	Flow visualization	en
dc.subject.other	Identification (control systems)	en
dc.subject.other	Oscillating cylinders	en
dc.subject.other	Pressure vessels	en
dc.subject.other	Reynolds number	en
dc.subject.other	Vortex flow	en
dc.subject.other	Wakes	en
dc.subject.other	Oscillating flow	en
dc.title	Computational study of flow resonances and forces on a cylinder vibrating in-line to a steady flow	en
heal.type	conferenceItem	en
heal.publicationDate	2010	en
heal.abstract	We present computational results of the flow dynamics and forces on a circular cylinder oscillating in-line with respect to a steady uniform stream. A wide range of oscillation frequencies is considered, from 0.5fs to 3fs, where fs is the natural Strouhal frequency of the Karman street. The oscillation amplitude is varied up to half the cylinder diameter. The Reynolds number value is 180, corresponding to two-dimensional flow. Simulations utilize a spectral element method. The computed flow states are characterized based on processed lift signals, and flow visualization. We find that the response of the flow is very sensitive to variations of the cylinder oscillation frequency. At low oscillation frequency, the lift signal and vortex patterns remain regular for low oscillation amplitudes, i.e. correspond to a 2S type of vortex street, and become complex at high oscillation amplitudes. Cylinder oscillation at the Strouhal frequency gives a window of chaotic flow at intermediate amplitudes, while at higher amplitudes 2S wakes are generated, with the sub-harmonic fs/2 and the higher harmonic 3fs/2 dominating the lift spectrum. Oscillation at twice the Strouhal frequency results in symmetric shedding, for oscillation amplitudes close to 30% of the cylinder diameter, and higher. Finally, at an oscillation frequency equal to three times the Strouhal frequency, the flow dynamics is very rich, characterized by ""islands"" of symmetric and asymmetric shedding at increasing oscillation amplitude. Chaotic flow is obtained only when the excitation frequency is equal to fs or to 3fs. Copyright © 2010 by ASME.	en
heal.journalName	American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP	en
dc.identifier.volume	4	en
dc.identifier.spage	193	en
dc.identifier.epage	200	en