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http://dx.doi.org/10.12989/was.2018.26.5.317

Features of the flow over a finite length square prism on a wall at various incidence angles  

Sohankar, A. (Department of Mechanical Engineering, Isfahan University of Technology)
Esfeh, M. Kazemi (Department of Mechanical Engineering, Isfahan University of Technology)
Pourjafari, H. (Department of Mechanical Engineering, Yazd University)
Alam, Md. Mahbub (Institute for Turbulence-Noise-Vibration Interaction and Control, Shenzhen Graduate School, Harbin Institute of Technology)
Wang, Longjun (Institute for Turbulence-Noise-Vibration Interaction and Control, Shenzhen Graduate School, Harbin Institute of Technology)
Publication Information
Wind and Structures / v.26, no.5, 2018 , pp. 317-329 More about this Journal
Abstract
Wake characteristics of the flow over a finite square prism at different incidence angles were experimentally investigated using an open-loop wind tunnel. A finite square prism with a width D = 15 mm and a height H = 7D was vertically mounted on a horizontal flat plate. The Reynolds number was varied from $6.5{\times}10^3$ to $28.5{\times}10^3$ and the incidence angle ${\alpha}$ was changed from $0^{\circ}$ to $45^{\circ}$. The ratio of boundary layer thickness to the prism height was about ${\delta}/H=7%$. The time-averaged velocity, turbulence intensity and the vortex shedding frequency were obtained through a single-component hotwire probe. Power spectrum of the streamwise velocity fluctuations revealed that the tip and base vortices shed at the same frequency as that ofspanwise vortices. Furthermore, the results showed that the critical incidence angle corresponding to the maximum Strouhal number and minimum wake width occurs at ${\alpha}_{cr}=15^{\circ}$ which is equal to that reported for an infinite prism. There is a reduction in the size of the wake region along the height of the prism when moving away from the ground plane towards the free end.
Keywords
experimental study; finite square prism; incidence angle; low-speed wind tunnel; hotwire; Strouhal number;
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1 Alam, M.M., Zhou, Y. and Wang, X.W. (2011), "The wake of two side-by-side square cylinders", J. Fluid Mech., 669, 432-471.   DOI
2 Alam, M.M., Bai, H.L. and Zhou, Y. (2016), "The wake of two staggered square cylinders", J. Fluid Mech., 801, 475-507.   DOI
3 Adaramola, M.S., Akinlade, O.G., Sumner, D., Bergstrom, D.J. and Schenstead, A.J. (2006), "Turbulent wake of a finite circular cylinder of small aspect ratio", J. Fluid. Struct., 22(6-7), 919-928.   DOI
4 Bourgeois, J.A., Sattari, P. and Martinuzzib, R.J. (2011), "Alternating half-loop shedding in the turbulent wake of a finite surface-mounted square cylinder with a thin boundary layer", Phys. Fluids, 23, 095101, 1-15.   DOI
5 Brun, C., Aubrun S., Goossens, T. and Ravier, Ph. (2008), "Coherent structures and their frequency signature in the separated shear layer on the sides of a square cylinder", J. Flow, Turbul. Combust., 81(1-2), 97-114.   DOI
6 Bruun, H.H. (1996), "Hot-wire anemometry, principles and signal analysis", OXFORD UNIVERSITY PRESS
7 Chen, J.M. and Liu, C.H. (1999), "Vortex shedding and surface pressures on a square cylinder at Incidence to a uniform Air Stream", Int. J. Heat Fluid Fl., 20, 592-597.   DOI
8 Dutta, S., Muralidhar, K. and Panigrahi, P.P. (2003), "Influence of the orientation of a square cylinder on the wake properties", Exp. Fluids, 34, 16-23.   DOI
9 Igarashi, T. (1984), "Characteristics of the flow around a square prism", Bull. JSME, 27, 1858-1865.   DOI
10 Huang, R.F., Lin, B.H. and Yen, S.C. (2010), "Time-averaged topological flow patterns and their Influence on vortex shedding of a square cylinder in cross flow at Incidence", J. Fluid. Struct., 26(3), 406-429.   DOI
11 Jorgenson, F. (2002), "How to measure turbulence with hot-wire anemometers" (A Practical Guide), Dantec Dynamics, Skovlunde, Denmark.
12 Lee, B.E. (1975), "The effect of turbulence on the surface pressure field of a square prism", J. Fluid Mech., 69, 263-282.   DOI
13 Lim, H.C. Castro, I.P. and Hoxey, R.P. (2007), "Bluff bodies in deep turbulent boundary layers: Reynolds-number issues", J. Fluid Mech., 571, 97-118.   DOI
14 Norberg, C. (1993), "Flow around rectangular cylinders: Pressure forces and wake frequencies", J. Wind Eng. Ind. Aerod., 49(1-3), 187-196.   DOI
15 Lyn, D.A., Einav, S., Rodi, W. and Park, J.H. (1995), "A laserdoppler velocimetry study of ensemble-averaged characteristics of the turbulent near wake of a square cylinder", J. Fluid Mech., 304, 285-319.   DOI
16 McClean, J.F. and Sumner. D. (2014), "An experimental investigation of aspect ratio and incidence angle effects for the flow around surface-mounted finite-height square prisms", J. Fluid. Eng., 136, 081206, 1-10.   DOI
17 Minguez, M., Brun, C., Pasquetti, R. and Serre, E. (2011), "Experimental and high order LES analysis of the near wall flow over a square cylinder", Int. J. Heat Fluid Fl., 32(3), 558-566.   DOI
18 Okamoto, H., and Sunabashiri, Y. (1992), "Vortex shedding from a circular cylinder of finite length placed on a ground plane", J. Fluids Eng., 114(4), 512-521.   DOI
19 Obasaju, E.D. (1983), "An investigation of the effects of incidence on the flow around a square section cylinder", J. Aero. Quart., 34(11), 243-259.   DOI
20 Okajima, A. (1982), "Strouhal numbers of rectangular cylinders", J. Fluid Mech., 123, 379-398.   DOI
21 Oudheusden, B.W.V., Scarano, F., Hinsberg, N.P.V. and Roosenboom, E.W.M. (2008), "Quantitative visualization of the flow around a square-section cylinder at incidence", J. Wind Eng. Ind. Aerod., 96(6-7), 913-922.   DOI
22 Park, C.W. and Lee, S.J. (2000), "Free end effects on the near wake flow structure behind a finite circular cylinder", J. Wind Eng. Ind. Aerod., 88(2-3), 231-246.   DOI
23 Rastan, M.R., Sohankar, A. and Alam, M.M. (2017), "Low-Reynolds-number flow around a wall-mounted square cylinder: flow structures and onset of vortex shedding", Phys. Fluids, 29, 103601, 1-19.   DOI
24 Sohankar, A., Norberg, C. and Davidson, L. (1999), "Simulation of unsteady 3D flow around a square cylinder at moderate Reynolds number", Phys. Fluids, 11(2), 288-306.   DOI
25 Rockwell, D.O. (1977), "Organized fluctuations due to flow past a square cross section cylinder", J. Fluids Eng., 99(3), 511-516.   DOI
26 Sakamoto, H. and Arie, M. (1983), "Vortex shedding from a rectangular prism and a circular cylinder placed vertically in a turbulent boundary layer", J. Fluid Mech., 126, 147-165.   DOI
27 Sakamoto, H. (1985), "Aerodynamic forces acting on a rectangular prism placed vertically in a turbulent boundary layer", J. Wind Eng. Ind. Aerod., 18(2), 131-151.   DOI
28 Sarode, R.S., Gai, S.L. and Ramesh, C.K. (1981), "Flow around circular-and square-section models of finite height in a turbulent shear flow", J. Wind Eng. Ind. Aerod., 8(3), 223-230.   DOI
29 Sohankar, A., Norberg, C. and Davidson, L. (1998), "Low-Reynolds number flow around a square cylinder at incidence: Study of blockage, onset of vortex shedding and outlet boundary condition", Int. J. Numer. Meth. Fl., 26, 39-56.   DOI
30 Sohankar, A., Davidson, L. and Norbeg, C. (2000), "Large eddy simulation of flow past a square cylinder: comparison of different subgrid scale models", J. Fluid. Eng., 122(1), 39-47.   DOI
31 Sohankar, A. (2006), "Flow over a bluff body from moderate to high Reynolds numbers using large eddy simulation", Comput. Fluids, 35(10), 1154-1168.   DOI
32 Sohankar, A. (2008), "Large eddy simulation of flow past rectangular section cylinders: Side ratio effects", J. Wind Eng. Ind. Aerod., 96(5), 640-655.   DOI
33 Sohankar, A., Mohagheghian, S., Dehghan, A.A. and Dehghan Manshadi, M. (2015), "A smoke visualization study of the flow over a square cylinder at incidence and tandem square cylinders", J. Visualization, 18(4), 687-703.   DOI
34 West, G.S. and Apelt, C.J. (1982), "The effects of tunnel blockage and aspect ratio on the mean flow past a circular cylinder with Reynolds numbers between 104 and 105", J. Fluid Mech., 114, 361-377.   DOI
35 Sumner, D., Heseltine, J.L. and Dansereau, O.J.P. (2004), "Wake structure of a finite circular cylinder of small aspect ratio", Exp. Fluids, 37(5), 720-730.   DOI
36 Trias, F.X. Gorobets, A. and Oliva A. (2015). "Turbulent flow around a square cylinder at Reynolds number 22,000: A DNS study", Comput. Fluids, 123 (22), 87-98.   DOI
37 Wang, H.F., Zhou, Y., Chan, C.K., Wong, W.O. and Lam., K.S. (2004) "Flow structure around a finite length square prism", Proceedings of the 15th Australasian Fluid Mechanics Conference, The University of Sydney, Sydney, Australia.
38 Wang, H.F., Zhou, Y., Chan, C.K. and Lam, K.S. (2006), "Effect of initial conditions on interaction between a boundary layer and a wall-mounted finite-length-cylinder wake", Phys. Fluids, 18, 065106, 1-12.   DOI
39 Wang, H.F. and Zhou, Y. (2009), "The finite-length square cylinder near wake", J. Fluid Mech., 638, 453-490.   DOI
40 Williamson C.H.K. (1996), "Three-dimensional wake transition", J. Fluid Mech., 328, 345-407.   DOI
41 Yavuzkurt, S. (1984), "A guide to uncertainty analysis of hot-wire data", J. Fluid. Eng., 106(2), 181-186.   DOI
42 Yen, S.C. and Yang, C.W. (2011), "Flow patterns and vortex shedding behavior behind a square cylinder", J. Wind Eng. Ind. Aerod., 99(8), 868-878.   DOI
43 Yen, S.C. and Yang, C.W. (2012), "Characteristic flow field behind a square-cylinder using upstream mesh fences", J. Fluid. Eng., 134(9), 091202-1-9.   DOI
44 Zdravkovich, M.M. (2003), "Flow around circular cylinders", 2, Applications. Oxford University Press.
45 Zheng, Q.M. and Alam, M.M. (2017), "Intrinsic features of flow past three square prisms in side-by-side arrangement", J. Fluid Mech., 826, 996-1033.   DOI