Joint PDF modelling of turbulent flow and dispersion in an urban street canyon

Preprint English OPEN
Bakosi, J. ; Franzese, P. ; Boybeyi, Z. (2010)
  • Related identifiers: doi: 10.1007/s10546-009-9370-x
  • Subject: Physics - Fluid Dynamics | 85A10, 76F25, 76F55, 76M35, 37N10 | Physics - Geophysics | Physics - Computational Physics

The joint probability density function (PDF) of turbulent velocity and concentration of a passive scalar in an urban street canyon is computed using a newly developed particle-in-cell Monte Carlo method. Compared to moment closures, the PDF methodology provides the full one-point one-time PDF of the underlying fields containing all higher moments and correlations. The small-scale mixing of the scalar released from a concentrated source at the street level is modelled by the interaction by exchange with the conditional mean (IECM) model, with a micro-mixing time scale designed for geometrically complex settings. The boundary layer along no-slip walls (building sides and tops) is fully resolved using an elliptic relaxation technique, which captures the high anisotropy and inhomogeneity of the Reynolds stress tensor in these regions. A less computationally intensive technique based on wall functions to represent boundary layers and its effect on the solution are also explored. The calculated statistics are compared to experimental data and large-eddy simulation. The present work can be considered as the first example of computation of the full joint PDF of velocity and a transported passive scalar in an urban setting. The methodology proves successful in providing high level statistical information on the turbulence and pollutant concentration fields in complex urban scenarios.
  • References (68)
    68 references, page 1 of 7

    Bacon, D. P., Ahmad, N. N., Boybeyi, Z., Dunn, T. J., Hall, M. S., Lee, P. C. S., Sarma, R. A., Turner, M. D., III., K. T. W., Young, S. H., Zack, J. W., 2000. A dynamically adapting weather and dispersion model: The Operational Multiscale Environment Model with Grid Adaptivity (OMEGA). Mon. Weather Rev. 128, 2044-2076.

    Baik, J.-J., Kim, J.-J., 1999. A numerical study of flow and pollutation dispersion characteristic in urban street canyons. J. Appl. Meteorol. 38, 1576-1589.

    Bakosi, J., Franzese, P., Boybeyi, Z., 2007. Probability density function modeling of scalar mixing from concentrated sources in turbulent channel flow. Phys. Fluids 19 (11), 115106. URL

    Bakosi, J., Franzese, P., Boybeyi, Z., 2008. A non-hybrid method for the PDF equations of turbulent flows on unstructured grids. J. Comput. Phys. 227 (11), 5896-5935.

    Cassiani, M., Franzese, P., Giostra, U., 2005a. A PDF micromixing model of dispersion for atmospheric flow. Part I: development of the model, application to homogeneous turbulence and to neutral boundary layer. Atmos. Environ. 39 (8), 1457-1469.

    Cassiani, M., Franzese, P., Giostra, U., 2005b. A PDF micromixing model of dispersion for atmospheric flow. Part II: application to convective boundary layer. Atmos. Environ. 39 (8), 1471-1479.

    Cassiani, M., Giostra, U., 2002. A simple and fast model to compute concentration moments in a convective boundary layer. Atmos. Environ. 36 (30), 4717-4724.

    Cassiani, M., Radicchi, A., Albertson, J. D., 2007. Modelling of concentration fluctuations in canopy turbulence. Boundary-Layer Meteorol. 122 (3), 655-681.

    Chatwin, P. C., Sullivan, P. J., 1993. The structure and magnitude of concentration fluctuations. BoundaryLayer Meteorol. 62, 269-280.

    Dopazo, C., 1994. Recent developments in pdf methods. In: Libby, P. A. (Ed.), Turbulent reactive flows. Academic, New York, pp. 375-474.

  • Similar Research Results (1)
  • Metrics
    No metrics available
Share - Bookmark