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Proper orthogonal decomposition analysis of vortex shedding behind a rotating circular cylinder

Sharul Sham Dol, P. Dančová, M. Veselý
2016 EPJ Web of Conferences  
Turbulence studies were made in the wake of a rotating circular cylinder in a uniform free stream with the objective of describing the patterns of the vortex shedding up to suppression of the periodic  ...  The results obtained in the present study establish that shedding of Kármán vortices in a rotating circular cylinder-generated wake is modified by rotation of the cylinder.  ...  Conclusion Turbulence studies were made in the wake of a rotating circular cylinder in a uniform free stream with the objective of describing the patterns of the vortex shedding up to suppression of the  ... 
doi:10.1051/epjconf/201611402019 fatcat:rfod42ayrnff5lotpbfr265gwe

Uncovering large-scale coherent structures in natural and forced turbulent wakes by combining PIV, POD, and FTLE

L. Kourentis, E. Konstantinidis
2011 Experiments in Fluids  
Two different cases are examined: unforced vortex shedding in the natural wake from the cylinder and vortex lock-on due to forced inflow perturbations.  ...  Velocity data of the unsteady separated flow in the turbulent wake of a circular cylinder obtained by PIV are analysed in order to visualize the large-scale coherent structures associated with periodic  ...  Application to PIV data The PIV data obtained in the natural and forced wake of a circular cylinder were analyzed using POD.  ... 
doi:10.1007/s00348-011-1124-0 fatcat:qcd5qxpvyvenpjrcvoj4g6awva

Passive jet control of flow around a circular cylinder

Wen-Li Chen, Dong-Lai Gao, Wen-Yong Yuan, Hui Li, Hui Hu
2015 Experiments in Fluids  
The PIV measurement results revealed clearly that the passive jet control method would cause airflow jets into the cylinder wake and change the shedding modes of the wake vortex structures from the cylindrical  ...  A linear stability analysis was performed to suggest that the passive jet flow would modify the wake stability of the circular cylinder by decreasing the disturbance growth rate in the immediate wake and  ...  ) for their thought-provoking discussions on linear stability analysis.  ... 
doi:10.1007/s00348-015-2077-5 fatcat:osm7gtmefnfthabbffx2tvsfwa

Three-dimensional vorticity patterns of cylinder wakes

Fulvio Scarano, Christian Poelma
2009 Experiments in Fluids  
The uncertainty analysis of the present tomographic PIV experiments reveals that this approach is suited for the investigation of vortex wakes with a typical error of 2 and 10% on the velocity and vorticity  ...  The vortex organization of cylinder wakes is experimentally studied by time-resolved tomographic Particle Image Velocimetry at Reynolds numbers ranging from 180 to 5,540.  ...  Acknowledgments The tomographic PIV system was kindly provided by LaVision GmbH. Bernd Wieneke is acknowledged for the support given on tomographic data analysis. Prof.  ... 
doi:10.1007/s00348-009-0629-2 fatcat:kmdxkguizjhbfazdx4lohhbukm

Cold-State Investigation on a Flame Holder

Yiqing Du
2013 Journal of Power and Energy Engineering  
The coherent structure of the near wake was identified by the vortex shedding simulation.  ...  Slitty bluff body is widely used as a high-performance flame holder in power industry.  ...  Yet the vortex shedding phenomena in PRZ over a slitty bluff body is largely the same as the near wake of a cylinder known as Von Karman vortex street.  ... 
doi:10.4236/jpee.2013.17008 fatcat:5glipkjyybcxve36zqr3ocv3te

Investigations into the Cylinder Flow Stabilities with a Thin Film Attachment

Deog-Hee Doh, Hyo-Je Jo, Seang-Yong Kwon, Hyoung-June Kim, Gyeang-Rae Cho, Byeong-Rog Shin
2011 Journal of the Korean Society of Marine Engineering  
The cylinder wakes have been measured with PIV experiments under the conditions with and without the thin film.  ...  For understanding the three-dimensional flow structures, a new Volumetric PTV(particle tracking velocimetry) has been constructed, in which the same four high-resolution cameras have been used.  ...  (a) without the thin film (b) with the thin film Figure 4 : 4 FFT analysis results on the PIV data at ReD=6160. This means that the flag controls the vortices at the downstream of the wake.  ... 
doi:10.5916/jkosme.2011.35.7.957 fatcat:etdnd5kxvraybe6isdrhbafskq

Unsteady aerodynamic forces estimation on a square cylinder by TR-PIV

D. F. Kurtulus, F. Scarano, L. David
2006 Experiments in Fluids  
The PIV measurements performed at a rate of 1 kHz enable a time resolved (TR) description of the vortex shedding phenomenon occurring at 10 Hz and to follow the time evolution of vortex dominated wake.  ...  The unsteady aerodynamic forces acting on a square cross-sectional cylinder are investigated by means of time-resolved particle image velocimetry (TR-PIV) at Reynolds number 4,900.  ...  The analysis of the time evolution of the lift coefficient returns a clear periodicity, in phase with the phenomenon of vortex shedding.  ... 
doi:10.1007/s00348-006-0228-4 fatcat:fxvjmbq7nzaebdook3oxnnb2ke

Proper Orthogonal Decomposition and Spectral Analysis of a Wall-Mounted Square Cylinder Wake

Henrique Fanini Leite, Ana Cristina Avelar, Leandra de Abreu, Daniel Schuch, André Cavalieri
2018 Journal of Aerospace Technology and Management  
The near wake fl ow structures and vortex shedding characteristics were investigated using mean fl ow analysis, spectral analysis and proper orthogonal decomposition (POD).  ...  Both symmetrical and anti-symmetrical vortices structures occur in the cylinder wake, which can be identifi ed based on the coeffi cients of the fi rst four POD modes.  ...  to the anteceding structure shed on the opposite side of the wake.  ... 
doi:10.5028/jatm.v10.867 fatcat:dsflnntjz5e5dhktzbz6n5h7rm

Time-Resolved PIV investigations of the flow field around cod-end net structures

Elkhadim Bouhoubeiny, Grégory Germain, Philippe Druault
2011 Fisheries Research  
It is then observed that the first POD modes are associated to the Karman's type flow structure of vortex shedding.  ...  It is shown that the characteristics of the wake flow behind the rigid cod-end flow configuration compare quite well with previous ones obtained from bluff cylinder or sphere wake analyzes.  ...  The authors also would like to acknowledge JV. Facq and B. Gaurier for their implication in the experimental work.  ... 
doi:10.1016/j.fishres.2011.01.010 fatcat:j2dmfttmqfbchguf3wmcilhh6q

Flow around a slotted circular cylinder at various angles of attack

Dong-Lai Gao, Wen-Li Chen, Hui Li, Hui Hu
2017 Experiments in Fluids  
notably delayed, the wake width behind the slotted cylinder was decreased and the vortex formation length was greatly shrunk, in comparison with the baseline case.  ...  Instantaneous pressure measurement results revealed that the pressure difference between the two slot ends and the periodically fluctuating pressure distributions would cause the alternative boundary layer  ...  Besides, the turbulent kinetic energy (TKE) values in the wake of the natural cylinder were found to be quite high, especially along the vortex shedding paths.  ... 
doi:10.1007/s00348-017-2417-8 fatcat:xl523yx4prgfdeqpgtg5wwnwpe

Vortex interaction in patches of randomly placed emergent cylinders [chapter]

Ana Ricardo, Simona Di Carlo, Mário Franca, Anton Schleiss, Pedro Sanches, Rui Ferreira
2014 River Flow 2014  
plane (uv component) against the time-averaged shear rate characteristic of vertical-axis vortex shedding in the wake of cylinders.  ...  horizontal plane (uv component) against the time-averaged shear rate characteristic of vertical-axis vortex shedding in the wake of cylinders.  ...  ACKNOWLEDGMENTS This research funded by the Portuguese Foundation for Science and Technology (FCT) through the project PTDC/ECM/117660/2010.  ... 
doi:10.1201/b17133-14 fatcat:dxsjh7ntcbdcvddn4a3cy5b6ra

Gap-flow patterns behind twin-cylinders at low Reynolds number

Shun Chang Yen, Chien Ting Liu
2011 Journal of Mechanical Science and Technology  
The flow structures, drag coefficients (C d ) and vortex shedding characteristics around a single square cylinder and twin side-by-side square cylinders were experimentally investigated with various Reynolds  ...  The maximum C d occurred in the single vortex-street mode, and the minimum C d occurred in the gap-flow mode.  ...  Kolar et al. indicated that the enhanced vortex motion and the average vortex speed in the base region were significantly high, even in the eventual near-wake equilibrium state (i.e., low vortex-speed  ... 
doi:10.1007/s12206-011-0908-8 fatcat:6lizb7yuvfh3bihtxu6wfc6mfu

Near Wake Behind an Airfoil with Leading-Edge Flow Control

Peter Gerontakos, Tim Lee
2005 Journal of Aircraft  
The representative effects of the cylinder rotation on the near- wake vortex shedding for Q =0-2.75 at a=4 and 14 deg with Re =7.7 x 10° are presented in Figs. 2-4.  ...  Fig. 5 Variation of a) vortex strength and b) wake mean velocity profile with 22. The definition of the vortex number is given in Fig. 3b. B.  ... 
doi:10.2514/1.9778 fatcat:n4oa5fdn65ft3j5hxblxw26bki

Spatiotemporal spectral analysis of a forced cylinder wake

Juan D'Adamo, Ramiro Godoy-Diana, José Eduardo Wesfreid
2011 Physical Review E  
A novel method based on the analysis of power density spectra of the flow allows us to give a detailed description of the forced wake, shedding light on the energy distribution in the different frequency  ...  components and in particular on a cascade-like mechanism evidenced for a high amplitude of the forcing oscillation.  ...  The present work was supported by the Franco-Argentinian Associated Laboratory in the Physics and Mechanics of Fluids (LIA PMF-FMF).  ... 
doi:10.1103/physreve.84.056308 pmid:22181499 fatcat:d2kw3qrdwvh2hfojuhnmor3i4y

Weakened Vortex Shedding From A Rotating Cylinder

Sharul S. Dol
2013 Zenodo  
The results indicate that the rotation of the cylinder causes significant changes in the vortex formation.  ...  Only part of the circulation is shed due to the interference in the separation point, mixing in the base region, re-attachment, and vortex cut-off phenomenon.  ...  Equipment was obtained through grants from the Canada Foundation for Innovation, the Ontario Innovation Trust, and the UWO Academic Development Fund.  ... 
doi:10.5281/zenodo.1088430 fatcat:om7fnufiyndkdjegp7hnfxkfsi
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