Boundary-Layer Meteorology

, Volume 143, Issue 2, pp 357–377 | Cite as

Geometric Dependence of the Scalar Transfer Efficiency over Rough Surfaces

  • Naoki Ikegaya
  • Aya Hagishima
  • Jun Tanimoto
  • Yudai Tanaka
  • Ken-ichi Narita
  • Sheikh Ahmad Zaki
Article

Abstract

We performed a series of wind-tunnel experiments under neutral conditions in order to create a comprehensive database of scalar transfer coefficients for street surfaces using regular block arrays representing an urban environment. The objective is to clarify the geometric dependence of scalar transfer phenomena on rough surfaces. In addition, the datasets we have obtained are necessary to improve the modelling of scalar transfer used for computational simulations of urban environments; further, we can validate the results obtained by numerical simulations. We estimated the scalar transfer coefficients using the salinity method. The various configurations of the block arrays were designed to be similar to those used in a previous experiment to determine the total drag force acting on arrays. Our results are summarized as follows: first, the results for cubical arrays showed that the transfer coefficients for staggered and square layouts varied with the roughness packing density. The results for the staggered layout showed the possibility that the mixing effect of air can be enhanced for the mid-range values of the packing density. Secondly, the transfer coefficients for arrays with blocks of non-uniform heights were smaller than those for arrays with blocks of uniform height under conditions of low packing density; however, as the packing density increased, the opposite tendency was observed. Thirdly, the randomness of rotation angles of the blocks in the array led to increasing values of the transfer coefficients under sparse packing density conditions when compared with those for cubical arrays.

Keywords

Salinity methodology Scalar transfer coefficient Urban building arrays Wind-tunnel experiment 

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References

  1. Barlow JF, Belcher SE (2002) A wind tunnel model for quantifying fluxes in the urban boundary layer. Boundary-Layer Meteorol 104: 131–150CrossRefGoogle Scholar
  2. Barlow JF, Harman IN, Belcher SE (2004) Scalar fluxes from urban street canyons. Part 1: laboratory simulation. Boundary-Layer Meteorol 113: 369–385CrossRefGoogle Scholar
  3. Boppana VB, Xie ZT, Castro IP (2010) Large-eddy simulation of dispersion from surface sources in arrays of obstacles. Boundary-Layer Meteorol 135: 433–454CrossRefGoogle Scholar
  4. Bransford S, Coceal O, Thomas TG, Belcher SE (2011) Dispersion of a point-source release of a passive scalar through an urban-like array for different wind directions. Boundary-Layer Meteorol 139: 367–394CrossRefGoogle Scholar
  5. Cai XM, Barlow JF, Belcher SE (2008) Dispersion and transfer of passive scalars in and above street canyons–large-eddy simulations. Atmos Environ 42: 5885–5895CrossRefGoogle Scholar
  6. Cheng H, Castro IP (2002) Near wall flow over urban-like roughness. Boundary-Layer Meteorol 104: 229–259CrossRefGoogle Scholar
  7. Cheng WC, Liu CH (2011) Large-eddy simulation of flow and pollutant transports in and above two-dimensional idealized street canyons. Boundary-Layer Meteorol 139: 411–437CrossRefGoogle Scholar
  8. Coceal O, Thomas TG, Castro IP, Belcher SE (2006) Mean flow and turbulence statistics over groups of urban-like cubical obstacles. Boundary-Layer Meteorol 121: 491–519CrossRefGoogle Scholar
  9. Coceal O, Thomas TG, Belcher SE (2007) Spatial variability of flow statistics within regular building arrays. Boundary-Layer Meteorol 125: 537–552CrossRefGoogle Scholar
  10. Counihan J (1971) Wind tunnel determination of the roughness length as a function of the fetch and the roughness density of three-dimensional roughness elements. Atmos Environ 5: 637–642CrossRefGoogle Scholar
  11. Farell C, Iyenger AKS (1999) Experiments on the wind tunnel simulation of atmospheric boundary layers. J Wind Eng Ind Aerodyn 79: 11–35CrossRefGoogle Scholar
  12. Hagishima A, Tanimoto J, Narita K-I (2005) Intercomparisons of experimental convective heat transfer coefficients and mass transfer coefficients of urban surfaces. Boundary-Layer Meteorol 117: 551–576CrossRefGoogle Scholar
  13. Hagishima A, Tanimoto J, Nagayama K, Meno S (2009) Aerodynamic parameters of regular arrays of rectangular blocks with various geometries. Boundary-Layer Meteorol 132: 315–337CrossRefGoogle Scholar
  14. Incropera F, DeWitte D (2002) Fundamentals of heat and mass transfer, 5th edn. Wiley, New YorkGoogle Scholar
  15. Iyenger AKS, Farell C (2011) Experimental issues in atmospheric boundary layer simulations: roughness length and integral length scale determination. J Wind Eng Ind Aerodyn 89: 1059–1080CrossRefGoogle Scholar
  16. Li X, Liu C, Leung DYC (2008) Large-eddy simulation of flow and pollutant dispersion in high-aspect-ratio urban street canyons with wall model. Boundary-Layer Meteorol 129: 249–268CrossRefGoogle Scholar
  17. Li X, Britter RE, Koh TY, Norford KK, Liu CH, Entekhabi D, Leung DYC (2010) Large-eddy simulation of flow and pollutant transport in urban street canyons with ground heating. Boundary-Layer Meteorol 137: 187–204CrossRefGoogle Scholar
  18. Michioka T, Sato A, Takimoto H, Kanda M (2010) Large-eddy simulation for the mechanism of pollutant removal from a two-dimensional street canyon. Boundary-layer Meteorol 138: 195–213CrossRefGoogle Scholar
  19. Narita KI (2007) Experimental study of the transfer velocity for urban surfaces with a water evaporation method. Boundary-Layer Meteorol 122: 293–320CrossRefGoogle Scholar
  20. Oke TR (1988) Street design and urban canopy layer climate. Energy Build 11: 103–113CrossRefGoogle Scholar
  21. Pascheke F, Barlow JF, Robins A (2008) Wind-tunnel modelling of dispersion from a scalar area source in urban-like roughness. Boundary-Layer Meteorol 126: 103–124CrossRefGoogle Scholar
  22. Raupach MR, Thom AS, Edward I (1980) A wind-tunnel study of turbulent flow close to regularly arrayed rough surfaces. Boundary-Layer Meteorol 18: 373–397CrossRefGoogle Scholar
  23. Snyder WH, Castro IP (2002) The critical Reynolds number for rough-wall boundary layers. J Wind Eng Ind Aerodyn 90: 41–54CrossRefGoogle Scholar
  24. Uehara K, Wakamatsu S, Ooka R (2003) Studies on critical Reynolds number indices for wind-tunnel experiments on flow within urban areas. Boundary-Layer Meteorol 107: 353–370CrossRefGoogle Scholar
  25. Wooding RA, Bradley EF, Marshall JK (1973) Drag due to regular arrays of roughness elements of varying geometry. Boundary-Layer Meteorol 5: 285–308CrossRefGoogle Scholar
  26. Xie ZT, Coceal O, Castro IP (2008) Large-eddy simulation of flows over random urban-like obstacles. Boundary-Layer Meteorol 129: 1–23CrossRefGoogle Scholar
  27. Zaki SA, Haghishima A, Tanimoto J, Ikegaya N (2011) Aerodynamic parameters of urban building arrays with random geometries. Boundary-Layer Meteorol 138: 99–120CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Naoki Ikegaya
    • 1
  • Aya Hagishima
    • 1
  • Jun Tanimoto
    • 1
  • Yudai Tanaka
    • 1
  • Ken-ichi Narita
    • 2
  • Sheikh Ahmad Zaki
    • 3
  1. 1.Interdisciplinary Graduate School of Engineering SciencesKyushu UniversityKasuga-shiJapan
  2. 2.Department of EngineeringNippon Institute of TechnologyMiyashiroJapan
  3. 3.Razak School of Engineering and Advanced TechnologyUniversity of Technology MalaysiaKuala LumpurMalaysia

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