Location of Repository

Modelling extreme concentration from a source in a turbulent flow over rough wall

By Zheng-Tong Xie, Paul Hayden, Alan G. Robins and Peter R. Voke


The concentration fluctuations in passive plumes from an elevated and a groundlevel source in a turbulent boundary layer over a rough wall were studied using large eddy simulation and wind tunnel experiment. The predictions of statistics up to second order moments were thereby validated. In addition, the trend of relative fluctuations far downstream for a ground level source was estimated using dimensional analysis. The techniques of extreme value theory were then applied to predict extreme concentrations by modelling the upper tail of the probability density function of the concentration time series by the Generalised Pareto Distribution. Data obtained from both the simulations and experiments were analysed in this manner. The predicted maximum concentration (?0) normalized by the local mean concentration (Cm) or by the local r.m.s of concentration fluctuation (crms), was extensively investigated. Values for ?0/Cm and ?0/crms as large as 50 and 20 respectively were found for the elevated source and 10 and 15 respectively for the ground-level source

Topics: TA, QC
Year: 2007
OAI identifier: oai:eprints.soton.ac.uk:45848
Provided by: e-Prints Soton

Suggested articles



  1. A generalised Pareto distribution model for high concentration in short-range atmospheric dispersion.
  2. A stochastic model for the motion of partical pairs in isotropic high-Reynolds-number turbulence, and it application to the problem of concentration variance,
  3. (1997). A switching Poisson process model for high concentration in short-range atmospheric dispersion.
  4. (1995). A unified approach to the design and application of bounded higher-order convection schemes,
  5. An introduction to statistical modelling of extreme values.
  6. and Robins A.G.,2004a. Large-eddy simulation of turbulent flow over a rough surface. Boundary-Layer Meteorol.
  7. Concentration fluctuation measurements in a dispersing plume at a range of up to 1000 m.
  8. Concentration fluctuations and fluxes in plumes from point sources in a turbulent boundary layer.
  9. (1989). Extreme value analysis of environmental time series: an application to trend detection in ground-level ozone.
  10. (2004). High Schmidt number scalars in turbulence: structure functions and Lagrangian theory.
  11. (2004). Large-eddy simulation of dispersion: comparison between elevated source and ground level source.
  12. LES of concentration fluctuations in a dispersing plume. Atmospheric Environment 26A,
  13. (1990). Models for exceedances over high thresholds (with discussion).
  14. (2000). Passive scalars in turbulent flows.
  15. Pourqui´ e M.B.J.M and Nieuwstadt F.T.M.,1999. Direct numerical simulation of turbulent mixing of a passive scalar in pipe flow.
  16. Statistical inference using extreme order statistics.
  17. (2001). The high concentration tails of the probability density function of a dispersing scalar in the atmosphere.

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.