Flow Control around Bluff Bodies by Attached Permeable Plates
The aim of present study is to control the unsteady flow structure downstream of a circular cylinder by use of attached permeable plates. Particle image velocimetry (PIV) technique and dye visualization experiments were performed in deep water and the flow characteristics were evaluated by means of time-averaged streamlines, Reynolds Shear Stress and Turbulent Kinetic Energy concentrations. The permeable plate was made of a chrome-nickel screen having a porosity value of β=0.6 and it was attached on the cylinder surface along its midspan. Five different angles were given to the plate (θ=0o, 15o, 30o, 45o, 60o) with respect to the centerline of the cylinder in order to examine its effect on the flow control. It was shown that the permeable plate is effective on elongating the vortex formation length and reducing the fluctuations in the wake region. Compared to the plain cylinder, the reductions in the values of maximum Reynolds shear stress and Turbulent Kinetic Energy were evaluated as 72.5% and 66%, respectively for the plate angles of θ=45oand 60o which were also found to be suggested for applications concerning the vortex shedding and consequent Vortex-Induced Vibrations.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1093042Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2248
 C. H. Kuo, L.C. Chiou, C. C. Chen, "Wake flow pattern modified by small control cylinders at low Reynolds number” inJournal of Fluids and Structures, vol. 23, pp. 938–956, 2007.
 S. Mittal, A. Raghuvanshi,"Control of vortex shedding behind circular cylinder for flows at low Reynolds numbers” inInternational Journal of Numerical Methods in Fluids, vol. 35, pp. 421–447, 1999.
 J.J. Wang, P.F. Zhang, S.F. Lu, K. Wu,"Drag reduction of a circular cylinder using an upstream rod” inFlow, Turbulence and Combustion vol. 76, pp. 83–101, 2006.
 H. Baek,G.E.Karniadakis, ”Suppressing vortex-induced vibrations via passive means” inJournal of Fluids and Structures,vol. 25, pp. 848–866, 2009.
 B.G. Dehkordi, H.H.Jafari,"On the suppression of vortex shedding from circular cylinders using detached short splitter-plates” inJournal of Fluid Eng-T ASME, vol. 132, pp. 044501, 2010.
 H. Akilli, C. Karakus,A. Akar, B. Sahin, N.F. Tumen,"Control of vortex shedding of circular cylinder in shallow water flow using an attached splitter plate” inJournal of Fluid Engineering-T ASME,vol. 130, pp. 041401, 2008.
 H. Akilli, B. Sahin, N.F.Tumen,"Suppression of vortex shedding of circular cylinder in shallow water by a splitter plate” inFlow Measurement Instrumentation, vol. 16, pp. 211–219, 2005.
 S. Turki,"Numerical simulation of passive control on vortex shedding behind square cylinder using splitter plate” inEngineering Applications of Computational Fluid Mechanics, vol. 2, pp. 514–524, 2008.
 S.B. Yucel, O. Cetiner, M.F. Unal,"Interaction of circular cylinder wake with a short asymmetrically located downstream plate” inExperiments in Fluids, vol. 49, pp. 241–255, 2010.
 K. Kwon, H. Choi,"Control of laminar vortex shedding behind a circular cylinder using splitter plates” inPhysics of Fluids,vol. 8, pp. 479–486, 1996.
 E. Rathakrishnan,"Effect of splitter-plate on bluff body drag” inAIAA Journal, vol. 37, pp. 1125–1126, 1999.
 M.F. Unal, D. Rockwell,"On vortex formation from a cylinder Part 2: Control by splitter plate interference” inJournal of Fluid Mechanics, vol. 190, pp. 513–529, 1988.
 H. Choi, W. Jeon, J. Kim,"Control of flow over a bluff body” inAnnual Review of Fluid Mechanics, vol. 40, pp. 113–139, 2008.
 G. M. Ozkan, V. Ouc, H.Akilli, B.Sahin, "Flow around a cylinder by a permeable outer cylinder in shallow water” inExperiments in Fluids, vol. 53, pp. 1751-1793, 2012.