Viscous oscillatory flow about a circular cylinder at small to moderate Strouhal number

Badr, H. M.; Dennis, S. C. R.; Kocabıyık, Serpil; Nguyen, Phu

doi:10.1017/s0022112095004241

Cited by 23 publications

(15 citation statements)

References 18 publications

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“…Also, the length of the separated zone is relatively independent of KC. This is in contrast to higher Reynolds number (Re > 100) studies [6][7][8] where vortex formation and shedding are primarily dependent on KC.…”

contrasting

confidence: 68%

“…Few studies [6][7][8] have been reported in the literature on the pulsatile flow past the stationary cylinder for Reynolds number (Re) >100 focusing on marine applications. As TAL operating Reynolds number is between 5 and 10, flow dynamics is expected to be different and no correlation can be made from studies available in the literature.…”

mentioning

confidence: 99%

“…As TAL operating Reynolds number is between 5 and 10, flow dynamics is expected to be different and no correlation can be made from studies available in the literature. [6][7][8] An apparent closely related class of a fluid mechanics problem 9 which involving cylinder oscillation in a quiescent or a low Reynolds number, also cannot be correlated with pulsatile flow over the fix cylinder case. As they are fundamentally different and Galilean transformation between them is not possible.…”

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confidence: 99%

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Pulsatility role in cylinder flow dynamics at low Reynolds number

2012

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We present dynamics of pulsatile flow past a stationary cylinder characterized by three non-dimensional parameters: the Reynolds number (Re), non-dimensional amplitude (A) of the pulsatile flow velocity, and Keulegan-Carpenter number (KC = Uo/Dωc). This work is motivated by the development of total artificial lungs (TAL) device, which is envisioned to provide ambulatory support to patients. Results are presented for 0.2 ≤ A ≤ 0.6 and 0.57 ≤ KC ≤ 2 at Re = 5 and 10, which correspond to the operating range of TAL. Two distinct fluid regimes are identified. In both regimes, the size of the separated zone is much greater than the uniform flow case, the onset of separation is function of KC, and the separation vortex collapses rapidly during the last fraction of the pulsatile cycle. The vortex size is independent of KC, but with an exponential dependency on A. In regime I, the separation point remains attached to the cylinder surface. In regime II, the separation point migrates upstream of the cylinder. Two distinct vortex collapse mechanisms are observed. For A < 0.4 and all KC and Re values, collapse occurs on the cylinder surface, whereas for A > 0.4 the separation vortex detaches from the cylinder surface and collapses at a certain distance downstream of the cylinder. The average drag coefficient is found to be independent of A and KC, and depends only on Re. However, for A > 0.4, for a fraction of the pulsatile cycle, the instantaneous drag coefficient is negative indicating a thrust production.

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confidence: 68%

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confidence: 99%

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confidence: 99%

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Pulsatility role in cylinder flow dynamics at low Reynolds number

2012

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“…However, a triad of two geometrical parameters and a velocity related parameter (Reynolds number or velocity itself) are not sufficient to define the problem entirely. Indeed a large body of literature related to the oscillatory flows past cylinders (Bearman et al 1985, Badr et al 1995, Lin et al 1996, Iliadis and Anagnostopoulos 1998 suggests that frequency of the forcing flow must appear in the problem description in one form or another. A widely accepted parameter of this kind is Keulegan-Carpenter number (KC), usually defined as (velocity)/(frequency x dimension).…”

Section: Similarity Issues -Geometry and Flow Parametersmentioning

confidence: 99%

PIV studies of coherent structures generated at the end of a stack of parallel plates in a standing wave acoustic field

Mao

Jaworski

et al. 2008

Exp Fluids

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ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request.1 PIV studies of coherent structures generated at the end of a stack of parallel plates in a standing wave acoustic field AbstractOscillating flow near the end of a stack of parallel plates placed in a standing wave resonator is investigated using Particle Image Velocimetry (PIV). The Reynolds number, Re d , based on the plate thickness and the velocity amplitude at the entrance to the stack, is controlled by varying the acoustic excitation (so-called drive ratio) and by using two configurations of the stacks. As the Reynolds number changes, a range of distinct flow patterns is reported for the fluid being ejected from the stack. Symmetrical and asymmetrical vortex shedding phenomena are shown and two distinct modes of generating "vortex streets" are identified.

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“…oscillatory flow forcing), not the frequency of the vortex shedding often investigated in steady flows past bluff bodies. This "forcing" Strouhal number has already been used such as in the study of the oscillatory flow around a circular cylinder (Badr et al, 1995).…”

Section: Normalisationmentioning

confidence: 99%

Oscillatory flow at the end of parallel-plate stacks: phenomenological and similarity analysis

Mao

Jaworski

2010

Fluid Dyn. Res.

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This paper addresses the physics of the oscillatory flow in the vicinity of a series of parallel plates forming geometrically identical channels. This type of flow is particularly relevant to thermoacoustic engines and refrigerators, where a reciprocating flow is responsible for the desirable energy transfer, but it is also of interest to general fluid mechanics of oscillatory flows past bluff bodies. In this paper the physics of an acoustically induced flow past a series of plates in an isothermal condition is studied in detail using the data provided by PIV imaging. Particular attention is given to the analysis of the wake flow during the ejection part of the flow cycle, where either closed re-circulating vortices or alternating vortex shedding can be observed. This is followed by a similarity analysis of the governing Navier-Stokes equations in order to derive the similarity criteria governing the wake flow behaviour. To this end, similarity numbers including two types of Reynolds number, Keulegan-Carpenter number and a non-dimensional stack configuration parameter, d/h are considered and their influence on the phenomena discussed.

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Viscous oscillatory flow about a circular cylinder at small to moderate Strouhal number

Cited by 23 publications

References 18 publications

Pulsatility role in cylinder flow dynamics at low Reynolds number

Pulsatility role in cylinder flow dynamics at low Reynolds number

PIV studies of coherent structures generated at the end of a stack of parallel plates in a standing wave acoustic field

Oscillatory flow at the end of parallel-plate stacks: phenomenological and similarity analysis

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