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Modeling flow and scalar dispersion around Cheomseongdae

  • Kim, Jae-Jin (Climate Environment System Research Center, Seoul National University) ;
  • Song, Hyo-Jong (School of Earth and Environmental Sciences, Seoul National University) ;
  • Baik, Jong-Jin (School of Earth and Environmental Sciences, Seoul National University)
  • 투고 : 2005.03.10
  • 심사 : 2006.06.08
  • 발행 : 2006.08.25

초록

Flow and scalar dispersion around Cheomseongdae are numerically investigated using a three-dimensional computational fluid dynamics (CFD) model with the renormalization group (RNG) $k-{\varepsilon}$ turbulence closure scheme. Cheomseongdae is an ancient astronomical observatory in Gyeongju, Korea, and is chosen as a model obstacle because of its unique shape, that is, a cylinder-shaped architectural structure with its radius varying with height. An interesting feature found is a mid-height saddle point behind Cheomseongdae. Different obstacle shapes and corresponding flow convergences help to explain the presence of the saddle point. The predicted size of recirculation zone formed behind Cheomseongdae increases with increasing ambient wind speed and decreases with increasing ambient turbulence intensity. The relative roles of inertial and eddy forces in producing cavity flow zones around an obstacle are conceptually presented. An increase in inertial force promotes flow separation. Consequently, cavity flow zones around the obstacle expand and flow reattachment occurs farther downwind. An increase in eddy force weakens flow separation by mixing momentum there. This results in the contraction of cavity flow zones and flow reattachment occurs less far downwind. An increase in ambient wind speed lowers predicted scalar concentration. An increase in ambient turbulence intensity lowers predicted maximum scalar concentration and acts to distribute scalars evenly.

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참고문헌

  1. Becker, S., Lienhart, H., and Durst, F. (2002), 'Flow around three-dimensional obstacles in boundary layers', J. Wind Eng. Ind. Aerodyn., 90, 265-279 https://doi.org/10.1016/S0167-6105(01)00209-4
  2. Brown, A.L. and Dabberdt, W.F. (2003), 'Modeling ventilation and dispersion for covered roadway', J. Wind Eng. Ind. Aerodyn., 91, 593-608 https://doi.org/10.1016/S0167-6105(02)00472-5
  3. Brown, M.J., Lawson Jr. R.E., DeCroix, D.S., and Lee, R.L. (2000), 'Mean flow and turbulence measurements around a 2-D array of buildings in a wind tunnel', 11th Joint Conference on the Applications of Air Pollution Meteorology with the A&WMA, Long Beach, January
  4. Castro, I.P. and Apsley, D.D. (1997), 'Flow and dispersion over topography: A comparison between numerical and laboratory data for two-dimensional flows', Atmos. Environ., 31, 839-850 https://doi.org/10.1016/S1352-2310(96)00248-8
  5. Chan, A.T., So, E.S.P., and Samad, S.C. (2001), 'Strategic guidelines for street canyon geometry to achieve sustainable street air quality', Almos. Environ., 35, 5681-5691 https://doi.org/10.1016/S1352-2310(01)00483-6
  6. Higson, H.L., Griffiths, R.F., Jones, C.D., and Hall, D.J. (1994), 'Concentration measurements around an isolated building: A comparison between wind tunnel and field data', Atmos. Environ., 28, 1827-1836 https://doi.org/10.1016/1352-2310(94)90322-0
  7. Hussein, H.J. and Martinuzzi, R.J. (1996), 'Energy balance for turbulent flow around a surface mounted cube placed in a channel', Phys. Fluids, 8, 764-780 https://doi.org/10.1063/1.868860
  8. Jiang, Y., Alexander, D., Jenkins, H., Arthur, R., and Chen, Q. (2003), 'Natural ventilation in buildings: Measurement in a wind tunnel and numerical simulation with large-eddy simulation', J. Wind Eng. Ind. Aerodyn., 91, 331-353
  9. Jones, C.D. and Griffiths, R.F. (1984), 'Full-scale experiments on dispersion around an isolated building using an ionized air tracer technique with very short averaging time', Atmos. Environ., 18, 903-916 https://doi.org/10.1016/0004-6981(84)90066-0
  10. Kim, J.-J., Baik, J.-J., and Chun, H.-Y. (2001), 'Two-dimensional numerical modeling of flow and dispersion in the presence of hill and buildings', J. Wind Eng. Ind. Aerodyn., 89, 947-966 https://doi.org/10.1016/S0167-6105(01)00092-7
  11. Kim, J.-J. and Baik, J.-J. (2003) 'Effects of inflow turbulence intensity on flow and pollutant dispersion in an urban street canyon', J. Wind Eng. Ind. Aerodyn., 91, 309-329 https://doi.org/10.1016/S0167-6105(02)00395-1
  12. Kim, J.-J. and Baik, J.-J. (2004), 'A numerical study of the effects of ambient wind direction on flow and dispersion in urban street canyons using the RNG ${\kappa}-{\varepsilon}$ turbulence model', Atmos. Environ., 38, 3039-3048 https://doi.org/10.1016/j.atmosenv.2004.02.047
  13. Lubcke, H., Schmidt, S., Rung, T., and Thiele, F. (2001), 'Comparison of LES and RANS in bluff-body flows', J. Wind Eng. Ind. Aerodyn., 89, 1471-1485 https://doi.org/10.1016/S0167-6105(01)00134-9
  14. Meroney, R.N., Leitl, B.M., Rafailidis, S., and Schatzmann, M. (1999), 'Wind-tunnel and numerical modeling of flow and dispersion about several building shapes', J. Wind Eng. Ind. Aerodyn., 81, 333-345 https://doi.org/10.1016/S0167-6105(99)00028-8
  15. Nigim, H.H. (1996), 'Recovery of equilibrium turbulent boundary layers downstream of obstacles', Phys. Fluids, 8, 548-554 https://doi.org/10.1063/1.868807
  16. Patankar, S.V. (1980), Numerical Heat Transfer and Fluid Flow, McGraw-Hill, New York
  17. Sada, K. and Sato, A. (2002), 'Numerical calculation of flow and stack-gas concentration fluctuation around a cubical building', Atmos. Environ., 36, 5527-5534 https://doi.org/10.1016/S1352-2310(02)00668-4
  18. Smith, W.S., Reisner, J.M., and Kao, C.-Y.J. (2001), 'Simulations of flow around a cubical building: Comparison with towing-tank data and assessment of radiatively induced thermal effects', Atmos. Environ., 35, 3811-3821 https://doi.org/10.1016/S1352-2310(01)00177-7
  19. Tutar, M. and Oguz, G. (2002), 'Large eddy simulation of wind flow around parallel buildings with varying configurations', Fluid Dyn. Res., 31, 289-315
  20. Yakhot, V. and Orszag, S.A. (1986), 'Renormalization group analysis of turbulence', J. Sci. Comp., 1, 3-51 https://doi.org/10.1007/BF01061452
  21. Yakhot, V., Orszag, S.A., Thangam, S., Gatski, T.B., and Speziale, C.G. (1992), 'Development of turbulence models for shear flows by a double expansion technique', Phys. Fluids, A4, 1510-1520