Wind and Structures

Techno-Press (테크노프레스)
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Detached eddy simulation of flow around rectangular bodies with different aspect ratios

  • Lim, Hee Chang (School of Mechanical Engineering, Pusan National University) ;
  • Ohba, Masaaki (Department of Architecture, Faculty of Engineering, Tokyo Polytechnic University)
  • Received : 2014.03.14
  • Accepted : 2014.11.01
  • Published : 2015.01.25
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Abstract

As wind flows around a sharp-edged body, the resulting separated flow becomes complicated, with multiple separations and reattachments as well as vortex recirculation. This widespread and unpredictable phenomenon has long been studied academically as well as in engineering applications. In this study, the flow characteristics around rectangular prisms with five different aspect ratios were determined through wind tunnel experiments and a detached eddy simulation, that placed the objects in a simulated deep turbulent boundary layer at $Re=4.6{\times}10^4$. A series of rectangular prisms with the same height (h = 80 mm), different longitudinal lengths (l = 0.5h, h, and 2h), or different transverse widths (w = 0.5h, h, and 2h) were employed to observe the effects of the aspect ratio. Furthermore, five wind directions ($0^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$, and $45^{\circ}$) were selected to observe the effects of the wind direction. The simulated results of the surface pressure were compared to the wind tunnel experiment results and the existing results of previous papers. The vortex and spectrum were also analyzed to determine the detailed flow structure around the body. The paper also highlights the pressure distribution around the rectangular prisms with respect to the different aspect ratios. With an increasing transverse width, the surface suction pressure on the top and side surfaces becomes stronger. In addition, depending on the wind direction, the pressure coefficient experiences a large variation and can even change from a negative to a positive value on the side surface of the cube model.

Keywords

Acknowledgement

Supported by : National Research Foundation of Korea(NRF)

References

  1. ANSYS Ltd. FLUENT User's Guide (2013), 14, 1-2428.
  2. Castro I.P. and Robins A.G. (1977), "The flow around a surface mounted cube in uniform and turbulent streams", J. Fluid Mech., 79, 307-335. https://doi.org/10.1017/S0022112077000172
  3. Cigada, A. and Malavasi, S. and Vanali, M. (2006), "Effects of an asymmetrical confined flow on a rectangular cylinder", J. Fluid. Struct., 22(2), 213-227. https://doi.org/10.1016/j.jfluidstructs.2005.09.006
  4. Cook, N.J. (1978), "Wind tunnel simulation of the adiabatic atmospheric boundary layer by roughness, barrier and mixing device methods", J. Wind Eng. Ind. Aerod., 3(2-3), 157-176. https://doi.org/10.1016/0167-6105(78)90007-7
  5. Diskin, B., Thomas, J.L., Nielsen, E.J., Nishikawa, H. and White, J.A. (2010), "Comparison of node-centered and cell-centered unstructured finite-volume discretizations: viscous fluxes", AIAA J., 48(7), 1326-1338. https://doi.org/10.2514/1.44940
  6. ESDU (1985), "Characteristics of atmospheric turbulence near the ground. Part II: single point data for strong winds (neutral atmosphere)", In Engineering Sciences Data Unit.
  7. Hunt, J.C.R. and Fernholz, H.H. (1975), "Wind-tunnel simulation of the atmospheric boundary layer", J. Fluid Mech., 70, 543-559. https://doi.org/10.1017/S0022112075002182
  8. Hussein, H. and Martinuzzi, R.J. (1996), "Energy balance for turbulent flow around a surface-mounted cube placed in a channel", Phys. Fluid, 8(3), 764-780. https://doi.org/10.1063/1.868860
  9. Jochen, F. and Dominic, V.T. (2008), "Hybrid LES/RANS methods for the simulation of turbulent flows", J Prog. Aerosp. Sci., 44(5), 349-377. https://doi.org/10.1016/j.paerosci.2008.05.001
  10. Larose, G.L. and D'Auteuil, A. (2008), "Experiments on 2D rectangular prisms at high Reynolds numbers in a pressurised wind tunnel", J. Wind Eng. Ind. Aerod., 96(6-7), 923-933. https://doi.org/10.1016/j.jweia.2007.06.018
  11. 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. https://doi.org/10.1017/S0022112006003223
  12. Lim, H.C. (2009), "Wind flow around rectangular obstacles with aspect ratio", Wind Struct., 12, 299-312. https://doi.org/10.12989/was.2009.12.4.299
  13. Lim, H.C., Thomas, T.G. and Castro, I.P. (2009), "Flow around a cube in a turbulent boundary layer: LES and experiment", J. Wind Eng. Ind. Aerod., 97(2), 96-109. https://doi.org/10.1016/j.jweia.2009.01.001
  14. Lozano-Duran, A. and Jimenez, J. (2014), "Effect of the computational domain on direct simulations of turbulent channels up to $Re_{\tau}$ =4200", Phys. of fluids, 26(1), 011702. https://doi.org/10.1063/1.4862918
  15. Martinuzzi, R. and Tropea, C. (1993), "The flow around surface-mounted, prismatic obstacles placed in a fully developed channel flow", J. Fluid Eng - T ASME., 115(1), 85-92.
  16. Matsumoto, M. and Yagi, T. and Tamaki, H. and Tsubota, T. (2008), "Vortex-induced vibration and its effect on torsional flutter instability in the case of B/D = 4 rectangular cylinder", J. Wind Eng. Ind. Aerod., 96(6-7), 971-983. https://doi.org/10.1016/j.jweia.2007.06.023
  17. Nozawa, K. and Tamura, T. (2002), "Large eddy simulation of the flow around a low-rise building immersed in a rough-wall turbulent boundary layer", J. Wind Eng. Ind. Aerod., 90(10), 1151-1162. https://doi.org/10.1016/S0167-6105(02)00228-3
  18. Pulliam, T. (1993), Time Accuracy and the Use of Implicit Methods, AIAA Paper 93-3360-CP.
  19. Richards, P.J. and Hoxey, P.J. and Short, L.J. (2001), "Wind pressure on a 6m cube", J. Wind Eng. Ind. Aerod., 89(14-15), 1553-1564. https://doi.org/10.1016/S0167-6105(01)00139-8
  20. Richards, P.J., Hoxey, R.P., Connell, B.D. and Lander, D.P. (2007), "Wind-tunnel modelling of the Silsoe cube", J. Wind Eng. Ind. Aerod., 95(9-11), 1384-1399. https://doi.org/10.1016/j.jweia.2007.02.005
  21. Rodi, W. (1997), "Comparison of LES and RANS calculations of the flow around bluff bodies", J. Wind Eng. Ind. Aerod., 69, 55-75.
  22. Salim, S.M. and Cheah, S.C. (2009), "Wall $y^{+}$ strategy for dealing with wall-bounded turbulent flows", Proceedings of the International MultiConference of Engineers and Computer Scientists, IMECS 2009, Hong Kong.
  23. Simiu, E. and Scanlan, R.H. (1996), Wind effects on structures - Fundamentals and applications to design, 3rd Ed., John Wiley, New York, USA.
  24. Schofield, W. and Logan, E. (1990) "Turbulent shear flow over surface-mounted obstacles", J. Fluid Eng.- T ASME, 112(4), 376-385. https://doi.org/10.1115/1.2909414
  25. Spalart, P.R., Jou, W.H., Strelets, M. and Allmaras, S.R. (1997), "Comments on the feasibility of LES for wings, and on a hybrid RANS/LES approach, Advances in DNS/LES", Proceedings of the 1st AFOSR Int. Conf On DNS/LES, Greyden Press, Columbus, OH, United States.
  26. Tieleman, H.W. and Akins, R.E. (1996), "The effect of incident turbulence on the surface pressures of surface-mounted prisms", J. Fluid. Struct., 10(4), 367-393. https://doi.org/10.1006/jfls.1996.0024
  27. Tominaga, Y. and Stathopoulos, T. (2010), "Numerical simulation of dispersion around an isolated cubic building: Model evaluation of RANS and LES", Build. Environ., 45(10), 2231-2239. https://doi.org/10.1016/j.buildenv.2010.04.004
  28. Xie, Z.T. and Castro, I.P. (2008), "Efficient generation of inflow conditions for large-eddy simulations of street-scale flows", Flow Turbul. Combust., 81(3), 449-470. https://doi.org/10.1007/s10494-008-9151-5
  29. Yakhot, A., Anor, T., Liu, H. and Nikitin, N. (2006a), "Direct numerical simulation of turbulent flow around a wall-mounted cube: spatio-temporal evolution of large-scale vortices", J. Fluid Mech., 566, 1-9. https://doi.org/10.1017/S0022112006002151
  30. Yakhot, A., Liu, H. and Nikitin, N. (2006b), "Turbulent flow around a wall-mounted cube: A direct numerical simulation", Int. J. Heat Fluid Fl., 27(6), 994-1009. https://doi.org/10.1016/j.ijheatfluidflow.2006.02.026

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