Experimental Study of the Downstream Flow of a Cylinder with Three Different Cross Sections by Hot Wire Anemometry

Document Type : Research Article

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Abstract

Drag and lift forces imposed on various bodies employed in engineering applications such as square and circular cylinders are highly dependent on the nature and characteristics of flow field around these structures. Therefore, the detailed investigation of the flow behavior around such bluff bodies has important engineering applications. In the present work, the characteristics of flow in the downstream of three different models with the circle and square cross sections is investigated in the wind tunnel using the hot wire anemometry. The blockage ratio for the circular and square cylinders at zero angle of attack is 2.2 percent, while it is 3.14 percent for the square cylinder with 45-degree angle of attack. For the model with a square cross section, the experiments were performed for both zero and 45-degree angle of attack. In this study, the effects of different Reynolds number and the cross-section of the cylinders are studied with the use of measured velocities and their fluctuation components. The Strouhal number and other flow characteristics in the downstream of the cylinder are compared with the published results in the literature. A good agreement is observed between the present results and the reported results. Comparing the result of three models showed that the reduced flow velocity behind 45 degrees orientated square cylinder in the interval X/D

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References

[1] Okajima, A., “Strouhal numbers of rectangular cylinders”, Journal Fluid Mechanics, Vol. 123, 379- 398, 1982.
[2] Zhou, Y., Antonia, R. A., “A study of turbulent vortices in the near wake of a cylinder”, J. Fluid Mech., 253, 643– 661,1993.
[3] Ong, L., Wallace, J., “The velocity field of the turbulent very near wake of a circular cylinder”, Experiments in Fluids, Vol. 20,441– 453, 1996.
[4] Shao, J., Zhang, C., “Numerical analysis of the flow around a circular cylinder using RANS and LES”, International Journal of Computational Fluid Dynamics, No. 5,301– 307, 2006.
[5] Saha, A. K., Muralidhar, K., Biswas, G., “Experimental study of flow past a square cylinder at high Reynolds numbers”,Experiments in Fluids, Vol. 29, 553– 63,2000.
[6] Lyn, D. A., Einav, S., Rodi W., Park, J. H. ,“A laser-Doppler velocimetry study of ensemble-averaged characteristics of the turbulent near wake of a square cylinder”,Journal Fluid Mechanics; Vol. 304, 285–
319, 1995.
[7] Wang, G., Choudhuri, PG., Bhandarkar MA. And Vanka, SP., “Large eddy simulations of bluff body wakes on parallel computer”, Report CFD 96-03, University of Illinois at Urbana Champaign, Contract
No. 0014-92-J-1334 of office of Naval Research, 1996.
[8] Sohankar, A., “Flow over a bluff body from moderate to high Reynolds numbers using large eddy simulation”, Computers & Fluids, Vol. 35, 1154– 1168, 2006.
[9] Ozgoren, M., “Flow structure in the downstream of square and circular cylinders”, Flow Measurement and Instrumentation, Vol. 17, 225– 235, 2006.
[10] Norberg, C., “Fluctuating lift on a circular cylinder: review and new measurements”,Journal of Fluids and Structures, Vol. 17,57– 96, 2003.
[11] Dutta, S., Muralidhar, K., Panigrahi P.K., “Influence of the orientation of a square cylinder on the wake properties”,Experiments in Fluids, Vol. 34, 16– 23,2003.
[12] Chen, J. M., Liu, CH., “Vortex shedding and surface pressures on a square cylinder at incidence to a uniform air stream”,International Journal of Heat and Fluid Flow, Vol. 20, 592– 597, 1999.
[13] Nakagawa, S., Nitta, K., Senda, M., “An experimental study on unsteady turbulent near wake of a rectangular cylinder in channel flow”, Experiments in Fluids, Vol.27(3), 284– 94, 1999.

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