PIV measurements of the wake behind a rotationally oscillating circular cylinder

Lee, Sang-Joon; Lee, Jung-Yeop

doi:10.1016/j.jfluidstructs.2007.06.001

Cited by 47 publications

(8 citation statements)

References 20 publications

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“…They also found drag reduction when F R was less than 1 at fixed oscillation amplitude of 30 • . Their second study (Lee & Lee 2008) was limited to one oscillation amplitude of 30 • and F R in the range from 0 to 1.6. They divided the near wake into three regimes: non-lock-on, transitional and lock-on depending on F R .…”

Section: Introductionmentioning

confidence: 99%

Flow past a rotationally oscillating cylinder

Kumar¹,

López²,

Probst

et al. 2013

J. Fluid Mech.

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Flow past a circular cylinder executing sinusoidal rotary oscillations about its own axis is studied experimentally. The experiments are carried out at a Reynolds number of 185, oscillation amplitudes varying from π/8 to π, and at non-dimensional forcing frequencies (ratio of the cylinder oscillation frequency to the vortex-shedding frequency from a stationary cylinder) varying from 0 to 5. The diagnostic is performed by extensive flow visualization using the hydrogen bubble technique, hotwire anemometry and particle-image velocimetry. The wake structures are related to the velocity spectra at various forcing parameters and downstream distances. It is found that the phenomenon of lock-on occurs in a forcing frequency range which depends not only on the amplitude of oscillation but also the downstream location from the cylinder. The experimentally measured lock-on diagram in the forcing amplitude and frequency plane at various downstream locations ranging from 2 to 23 diameters is presented. The far-field wake decouples, after the lock-on at higher forcing frequencies and behaves more like a regular Bénard-von Kármán vortex street from a stationary cylinder with vortex-shedding frequency mostly lower than that from a stationary cylinder. The dependence of circulation values of the shed vortices on the forcing frequency reveals a decay character independent of forcing amplitude beyond forcing frequency of ∼1.0 and a scaling behaviour with forcing amplitude at forcing frequencies 1.0. The flow visualizations reveal that the far-field wake becomes two-dimensional (planar) near the forcing frequencies where the circulation of the shed vortices becomes maximum and strong three-dimensional flow is generated as mode shape changes in certain forcing parameter conditions. It is also found from flow visualizations that even at higher Reynolds number of 400, forcing the cylinder at forcing amplitudes of π/4 and π/2 can make the flow field two-dimensional at forcing frequencies greater than ∼2.5.

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Section: Introductionmentioning

confidence: 99%

Flow past a rotationally oscillating cylinder

Kumar¹,

López²,

Probst

et al. 2013

J. Fluid Mech.

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“…The various passive control devices were comprehensively discussed by Zdravkovich (1997). For the latter, heating the cylinder (Lecordier et al, 1991), rotary oscillation of the cylinder at an appropriate frequency (Lee and Lee, 2008;Naim et al, 2007), acoustics excitations (Blevins, 1985), and control of the electromagnetic force (Kim and Lee, 2001) can be remarked as the sample investigations. The passive control methods (Lam et al, 2010;Zhou et al, 2011) are still developed since there is no external energy input and no feedback sensor; furthermore they are easier to carry out than the active control methods which require actuation as well as sensing.…”

Section: Introductionmentioning

confidence: 99%

Passive control of flow structures around a circular cylinder by using screen

Oruç

2012

Journal of Fluids and Structures

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“…Experimental studies have been performed by Tokumaru & Dimotakis (1991), Fujisawa, Kawaji & Ikemoto (2001), Fujisawa, Tanahashi & Srinivas (2005), Lee & Lee (2006), Saad, Lee & Lee (2007), Lee & Lee (2008), Nazarinia et al (2012) and, most recently, Kumar et al (2013) 552 P. Sellappan and T. Pottebaum and Sellappan & Pottebaum (2014). Tokumaru & Dimotakis (1991) conducted an experimental study at Re = 15 000, performing flow visualization and wake profile measurements on circular cylinders undergoing forced rotary oscillations in a steady uniform flow and found that the drag forces on the cylinder were reduced at high oscillation frequencies while undergoing rotary forcing.…”

Section: Vortex Shedding From Cylindersmentioning

confidence: 99%

“…They conducted experiments with forcing frequencies up to two times the natural shedding frequency and found locked-on wake structures in the wake of a rotationally oscillating cylinder at Re = 4140. Further detailed PIV measurements of the near-wake when the cylinder is forced with an oscillation amplitude θ PP = 1.04 and frequency ratios F R = 0.4, 0.8, 1.0, 1.6 at Re = 4140 were given by Lee & Lee (2008). They also found the wake to be locked-on to the forcing when F R = 1.0, but observed only a transition regime when F R = 0.8, 1.6 and a non-lock-on regime when F R = 0.4.…”

Section: Vortex Shedding From Cylindersmentioning

confidence: 99%

“…The locations of the mode boundaries in the θ PP − F R parameter space are approximate. In the case of data from Lee & Lee (2008), the lock-on boundaries are drawn such that they are approximately equidistant between the locked-on data point at F R = 1.0 and the transition regime data points on either side. The existence of the primary lock-on region centred around the Strouhal frequency for different values of Re is apparent from figure 3.…”

Section: Vortex Shedding From Cylindersmentioning

confidence: 99%

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Vortex shedding and heat transfer in rotationally oscillating cylinders

Sellappan

Pottebaum

2014

J. Fluid Mech.

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Wake formation and heat transfer from a rotationally oscillating circular cylinder in cross-flow at Re = 750 are studied. Two aspects, the effect of cylinder forcing on vortex shedding and the effect of the wake structures on convective heat transfer, are studied. Cylinder forcing conditions range between 0.09 θ PP 2.09, where θ PP is the peak-to-peak oscillation amplitude in radians and 0.70 F R 3.16, where F R is the ratio of forcing frequency to natural shedding frequency. Digital particle image velocimetry (DPIV) is used to obtain quantitative wake structure information. Wake modes, and regions of the parameter space in which they occur, are identified for both heated and unheated cylinders. For the heated cylinder, cylinder forcing is found to affect the convective heat-transfer rate. Certain wake modes, including newly discovered wake modes synchronized over multiple oscillation cycles, are found to correlate with significant heat-transfer enhancement. Cylinder tangential velocity is also found to affect the heat-transfer rate in certain regions of the parameter space.

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PIV measurements of the wake behind a rotationally oscillating circular cylinder

Cited by 47 publications

References 20 publications

Flow past a rotationally oscillating cylinder

Flow past a rotationally oscillating cylinder

Passive control of flow structures around a circular cylinder by using screen

Vortex shedding and heat transfer in rotationally oscillating cylinders

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