Skip to main content

Advertisement

SpringerLink
Log in

On thermally forced flows in urban street canyons

  • Original Article
  • Published:
Environmental Fluid Mechanics Aims and scope Submit manuscript

Abstract

During sunny days with periods of low synoptic wind, buoyancy forces can play a critical role on the air flow, and thus on the dispersion of pollutants in the built urban environments. Earlier studies provide evidence that when a surface inside an urban street canyon is at a higher temperature than that of local ambient air, buoyancy forces can modify the mechanically-induced circulation within the canyons (i.e., gaps between buildings). The aspect ratio of the urban canyon is a critical factor in the manifestation of the buoyancy parameter. In this paper, computational fluid dynamics simulations are performed on urban street canyons with six different aspect ratios, focusing on the special case where the leeward wall is at a greater temperature than local ambient air. A non-dimensional measure of the influence of buoyancy is used to predict demarcations between the flow regimes. Simulations are performed under a range of buoyancy conditions, including beyond those of previous studies. Observations from a field experiment and a wind tunnel experiment are used to validate the results.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9

Similar content being viewed by others

References

  1. Allegrini J, Dorer V, Carmeliet J (2013) Wind tunnel measurements of buoyant flows in street canyons. Build Environ 59:315–326

    Article  Google Scholar 

  2. ANSYS Inc. (2012) ANSYS Fluent 14.0 Theory Guide

  3. Britter RE, Hanna SR (2003) Flow and dispersion in urban areas. Ann Rev Fluid Mech 35(1):469–496

    Article  Google Scholar 

  4. Cai X (2012) Effects of wall heating on flow characteristics in a street canyon. Bound-Lay Meteorol 142(3):443–467

    Article  Google Scholar 

  5. Cai X (2012) Effects of differential wall heating in street canyons on dispersion and ventilation characteristics of a passive scalar. Atmos Environ 51:268–277

    Article  Google Scholar 

  6. Castro IP, Robins AG (1977) The flow around a surface-mounted cube in uniform and turbulent streams. J Fluid Mech 79(02):307–335

    Article  Google Scholar 

  7. Dallman A, Magnusson S, Britter RE, Norford L, Entekhabi D, Fernando HJS (2014) Conditions for thermal circulation in urban street canyons. Build Environ

  8. Department of Economic and Social Affairs (UN DESA). (2012) World Urbanization Prospects 2011 highlights. Technology. http://www.slideshare.net/undesa/wup2011-highlights Accessed 30 Apr 2012

  9. Fernando HJS, Zajic D, Di Sabatino S, Dimitrova R, Hedquist B, Dallman A (2010) Flow, turbulence, and pollutant dispersion in urban atmospheres. Phys Fluids 22(5):051301

    Article  Google Scholar 

  10. Kim JJ, Baik JJ (1999) A numerical study of thermal effects on flow and pollutant dispersion in urban street canyons. J Appl Meteorol 38(9):1249–1261

    Article  Google Scholar 

  11. Kim JJ, Baik JJ (2004) A numerical study of the effects of ambient wind direction on flow and dispersion in urban street canyons using the RNG k-\(\varepsilon \) turbulence model. Atmos Environ 38(19):3039–3048

    Article  Google Scholar 

  12. Li XX, Britter RE, Koh TY, Norford L, Liu CH, Entekhabi D, Leung DYC (2010) Large-Eddy simulation of flow and pollutant transport in urban street canyons with ground heating. Bound-Lay Meteorol 137(2):187–204

    Article  Google Scholar 

  13. Li XX, Britter RE, Norford L, Koh TY, Entekhabi D (2012) Flow and pollutant transport in urban street canyons of different aspect ratios with ground heating: Large-Eddy simulation. Bound-Lay Meteorol 142:289–304

    Article  Google Scholar 

  14. Look P, Belcher S, Harrison R (2000) Coupling between air flow in streets and the well-developed boundary layer aloft. Atmos Environ 34(16):2613–2621

    Article  Google Scholar 

  15. Louka P, Vachon G, Sini JF, Mestayer PG, Rosant JM (2002) Thermal effects on the airflow in a street canyon—Nantes’99 experimental results and model simulations. Water Air Soil Pollut 2(5–6):351–364

    Article  Google Scholar 

  16. Oke TR (1988) Street design and urban canopy layer climate. Energy Build 11(1):103

    Article  Google Scholar 

  17. Park SB, Baik JJ, Raasch S, Letzel MO (2012) A Large-Eddy simulation study of thermal effects on turbulent flow and dispersion in and above a street canyon. J Appl Meteorol Climatol 51(5):829–841

    Article  Google Scholar 

  18. Richards PJ, Hoxey RP (1993) Appropriate boundary conditions for computational wind engineering models using the \(k-\epsilon \) turbulence model. J Wind Eng Ind Aerodyn 46–47:145–153

    Article  Google Scholar 

  19. Sini JF, Anquetin S, Mestayer PG (1996) Pollutant dispersion and thermal effects in urban street canyons. Atmos Environ 30(15):2659–2677

    Article  Google Scholar 

  20. Solazzo E, Britter RE (2007) Transfer processes in a simulated urban street canyon. Bound-Lay Meteorol 124(1):43

    Article  Google Scholar 

  21. Stull RB (1988) An Introduction to boundary layer meteorology. Springer, Berlin and New York

    Book  Google Scholar 

  22. Turner JS (1979) Buoyancy effects in fluids. Cambridge University Press, Cambridge

    Google Scholar 

Download references

Acknowledgments

This research was supported by the Singapore National Research Foundation through the Singapore-MIT Alliance for Research and Technology’s Center for Environmental Sensing and Modeling (CENSAM). During the preparation of this paper, H.J.S. Fernando was supported by National Science Foundation (CMG; Grant # 0934592). The authors would like to thank the two reviewers for their useful comments and suggestions.

Author information

Authors and Affiliations

  1. Department of Civil- and Environmental Engineering, Parsons Laboratory, Massachusetts Institute of Technology, Cambridge, MA , 02139, USA

    S. Magnusson & D. Entekhabi

  2. Center for Environmental Sensing and Modeling, Singapore-MIT Alliance for Research and Technology, Singapore , 138062, Singapore

    S. Magnusson, D. Entekhabi, R. Britter & L. Norford

  3. Department of Civil- and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN , 46556, USA

    A. Dallman & H. J. S. Fernando

  4. Department of Architecture, Building Technology Program, Massachusetts Institute of Technology, Cambridge, MA , 02139, USA

    R. Britter & L. Norford

Authors
  1. S. Magnusson
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. A. Dallman
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. D. Entekhabi
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. R. Britter
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. H. J. S. Fernando
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. L. Norford
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to S. Magnusson.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Magnusson, S., Dallman, A., Entekhabi, D. et al. On thermally forced flows in urban street canyons. Environ Fluid Mech 14, 1427–1441 (2014). https://doi.org/10.1007/s10652-014-9353-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10652-014-9353-4

Keywords

Search

Navigation