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http://dx.doi.org/10.7837/kosomes.2019.25.6.795

Skin-Friction Drag Reduction in Wake Region by Suction Control on Horseshoe Vortex in front of Hemisphere  

Koo, Bonguk (Department of Naval Architecture and Marine Engineering, Changwon University)
Kang, Yong-Duck (Department of Naval Architecture and Ocean Engineering, Dong-Eui University)
Publication Information
Journal of the Korean Society of Marine Environment & Safety / v.25, no.6, 2019 , pp. 795-801 More about this Journal
Abstract
The aim of this study was to investigate the possibility of the skin-friction reduction by vortex control. A vortical system such as a horseshoe vortex, a hairpin vortex, and a wake region was induced around a hemisphere attached on a Perspex flat plate in the circulating water channel. Hairpin vortices were developed from the wake region and horseshoe vortices were formed by an adverse pressure gradient in front of the hemisphere. The horseshoe vortices located on the flank of the hemisphere induced a high momentum flow in the wake region by the direction of their vorticity. This process increased the frequency of the hairpin vortices as well as the frictional drag on the surface of the wake region. To reduce the skin-friction drag, suction control in front of the hemisphere was applied through a hole. Flow visualization was performed to optimize the free-stream velocity, size of the hemisphere, and size of the suction hole. Once the wall suction control mitigated the strength of the horseshoe vortex, the energy supplied to the wake region was reduced, causing the frequency of the hairpin vortex generation to decrease by 36.4 %. In addition, the change in the skin-friction drag, which was measured with a dynamometer connected to a plate in the wake region, also decreased by 2.3 %.
Keywords
Horseshoe vortex; Wall suction control; Hairpin vortex; Shedding frequency; Skin-friction drag; Dynamometer;
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  • Reference
1 Abe, H., H. Kawamura, and Y. Matsuo(2001), Direct Numerical Simulation of a Fully Developed Turbulent Channel Flow with Respect to the Reynolds Number Dependence, Transactions of the ASME, 123, pp. 382-393.
2 Balakumar, P. and E. Widnall(1986), Application of Unsteady Aerodynamics to Large-Eddy Breakup Devices in a Turbulent Flow, Phys. Fluids, 29, No. 6, pp. 1779-1787.   DOI
3 Doligalski, T. L., C. R. Smith, and J. D. A. Walker(1994), Vortex Interactions with Walls, Ann. Rev. Fluid Mech., Vol. 26, pp. 573-616.   DOI
4 Glezer, A.(1998), The Formation of Vortex Rings, Phys. Fluids, 31, No. 12, pp. 3532-3542.   DOI
5 Guezennec, Y. G. and H. M. Nagib(1990), Drag Reduction in Turbulent Boundary Layers, AIAA J., 28, p. 245.   DOI
6 Gupta, A. K.(1987), Hydrodynamic Modification of the Horseshoe Vortex at a Vertical Pier Junction with Ground, Phys. Fluids, 30, No. 4, pp. 1213-1215.   DOI
7 Hung, C. M., C. H. Sung, and C. L. Chen(1992), Computation of Saddle Point of Attachment, AIAA J., 30, No. 6, pp. 1561-1569.   DOI
8 Hutchins, N. and K. S. Choi(2002), Towards a Greater Understanding of Turbulent Skin-Friction Reduction, Proceedings of the ASME FEDSM, Paper No. 2002-31060.
9 Iwamoto, K., Y. Suzuki, and N. Kasagi(2002), Reynolds Number Effect on Wall Turbulence: Toward Effective Feedback Control, Int. J. Heat and Fluid Flow, 23, pp. 678-689.   DOI
10 James, S. and C. K. Madnia(1996), Direct Numerical Simulation of a Laminar Vortex Ring, Phys. Fluids, 8, No. 9, pp. 2400-2414.   DOI
11 Kang, Y. D., K. S. Choi, and H. H. Chun(2008), Direct Intervention of Hairpin Structures for Turbulent Boundary-Layer Control, Phys. Fluids, 20, pp. 101517-1-101517-13.   DOI
12 Kline, S. J., W. C. Reynolds, F. A. Schraub, and P. W. Runstadler(1967), The Structure of Turbulent Boundary Layer, J. Fluid Mech., 30, pp. 741-773.   DOI
13 Schlichting, H.(1968), Boundary-Layer Theory, McGraw-Hill
14 Maxworthy, T.(1977), Some Experimental Studies of Vortex Rings, J. Fluid Mech., 81, pp. 465-495.   DOI
15 Pullin, D. I.(1979), Vortex Ring Formation at Tube and Orifice Openings, Phys. Fluids, 22, No. 3, pp. 401-403.   DOI
16 Robinson, S. K.(1990), A Perspective on Coherent Structures and Conceptual Models for Turbulent Boundary Layer Physics, AIAA Paper No. 90-1638, pp. 1-16.
17 Sahlin, A., A. V. Johansson, and P. H. Alfredsson(1988), The Possibility of Drag Reduction by Outer Layer Manipulators in Turbulent Boundary Layers, Phys. Fluids, 31, No. 10, pp. 2814-2820.   DOI
18 Visbal, M. R.(1991), Structure of Laminar Juncture Flows, AIAA J., 29, No.8, pp. 1273-1282.   DOI
19 Toy, N. and E. Savory(1983), Turbulent Shear Flow in the Near Wake of a Hemisphere, Proceedings of the 8th Symposium on Turbulence, pp. 145-156.
20 Tufo, H. M., P. F. Fischer, M. E. Papka, and M. Szymanski(1999), Hairpin Vortex Formation, a Case Study for Unsteady Visualisation, 41st CUG Conference.
21 Zondag, H. A.(1997), The Dynamics of Hairpin Vortices in a Laminar Boundary Layer, PhD Thesis, University of Eindhoven.