Abstract
Measurements of concentration fluctuation intensity, intermittency factor, and integral time scale were made in a water channel for a plume dispersing in a well-developed, rough surface, neutrally stable, boundary layer, and in grid-generated turbulence with no mean velocity shear. The water-channel simulations apply to full-scale atmospheric plumes with very short averaging times, on the order of 1–4 min, because plume meandering was suppressed by the water-channel side walls. High spatial and temporal resolution vertical and crosswind profiles of fluctuations in the plume were obtained using a linescan camera laser-induced dye tracer fluorescence technique. A semi-empirical algebraic mean velocity shear history model was developed to predict these concentration statistics. This shear history concentration fluctuation model requires only a minimal set of parameters to be known: atmospheric stability, surface roughness, vertical velocity profile, and vertical and crosswind plume spreads. The universal shear history parameter used was the mean velocity shear normalized by surface friction velocity, plume travel time, and local mean wind speed. The reference height at which this non-dimensional shear history was calculated was important, because both the source and the receptor positions influence the history of particles passing through the receptor position.
Similar content being viewed by others
References
Bara BM, Wilson DJ, Zelt BW (1992) Concentration fluctuation profiles from a water channel simulation of a ground-level release. Atmos Environ 26A(6): 1053–1062
Cassiani M, Giostra U (2002) A simple and fast model to compute concentration moments in a convective boundary layer. Atmos Environ 36: 4717–4724
Deardorff JW, Willis GE (1984) Groundlevel concentration fluctuations from a buoyant and a non-buoyant source within a laboratory convectively mixed layer. Atmos Environ 18(7): 1297–1309
Fackrell JE, Robins AG (1982a) Concentration fluctuations and fluxes in plumes from point sources in a turbulent boundary layer. J Fluid Mech 117: 1–26
Fackrell JE, Robins AG (1982b) The effects of source size on concentration fluctuations in plumes. Boundary-Layer Meteorol 22: 335–350
Gifford F (1959) Statistical properties of a fluctuating plume dispersion model. In: Proceedings of symposium on atmospheric diffusion and air pollution. Academic Press, New York, pp 117–137
Hanna SR, Drivas PJ, Chang JJ (1996) Guidelines for use of vapor cloud dispersion models, 2nd edn. Center for Chemical Process Safety of the American Institute of Chemical Engineers, New York, NY, p 271
Hilderman T, Wilson DJ (2007) Predicting plume meandering and averaging time effects on mean and fluctuating concentrations in atmospheric dispersion simulated in a water channel. Boundary-Layer Meteorol 122: 535–575
Hilderman TL, Wilson DJ (1999) Simulating concentration fluctuation time series with intermittent zero periods and level dependent derivatives. Boundary-Layer Meteorol 91: 451–482
Hinze J (1975) Turbulence, 2nd edn. McGraw-Hill, New York, p 790
Hogrefe C, Vempaty S, Rao ST, Porter PS (2003) A comparison of four techniques for separating different time scales in atmospheric variables. Atmos Environ 37: 313–325
Kerschgens MJ, Nolle C, Martens R (2000) Comments on turbulence parameters for the calculation of dispersion in the atmospheric boundary layer. Meteorol Z 9(3): 155–163
Luhar AK, Hibberd MF, Borgas MS (2000) A skewed meandering plume model for concentration statistics in the convective boundary layer. Atmos Environ 34: 3599–3616
Mylne KR (1993) The vertical profile of concentration fluctuations in near-surface plumes. Boundary-Layer Meteorol 65: 111–136
Pasquill F, Smith F (1983) Atmospheric diffusion 3 edn. Wiley, London, p 437
Sawford BL (2004) Conditional scalar mixing statistics in homogeneous isotropic turbulence. New J Phys 6: 55
Sawford BL, Stapountzis H (1986) Concentration fluctuations according to fluctuating plume models in one and two dimensions. Boundary-Layer Meteorol 37: 89–105
Smith FB (1965) The role of wind shear in horizontal diffusion of ambient particles. Quart J Roy Meteorol Soc 91: 318–329
Sykes RI (1988) Concentration fluctuations in dispersing plumes. In: Lectures on air pollution modelling. Amer Meterol Society, Boston, pp 325–336
Sykes RI, Henn DS (1992) Large-eddy simulation of concentration fluctuations in a dispersing plume. Atmos Environ 26A: 3127–3142
Wilson D (1981) Along-wind diffusion of source transients. Atmos Environ 15: 489–495
Wilson DJ (1995) Concentration fluctuations and averaging time in vapor clouds. Center for Chemical Process Safety of the American Institute of Chemical Engineers, New York, NY, p 181
Wilson DJ, Zelt BW (1990) Technical basis for EXPOSURE-1 and SHELTER-1 models for predicting outdoor and indoor exposure hazards from toxic gas releases. Engineering report 72, University of Alberta Department of Mechanical Engineering, 53 pp
Wilson DJ, Robins AG, Fackrell JE (1985) Intermittency and conditionally-averaged concentration fluctuation statistics in plumes. Atmos Environ 19: 1053–1064
Yee E, Chan R, Kosteniuk P, Chandler G, Biltoft C, Bowers J (1995) The vertical structure of concentration fluctuation statistics in plumes dispersing in the atmospheric surface layer. Boundary-Layer Meteorol 76: 41–67
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Hilderman, T., Wilson, D.J. Effect of Vertical Wind Shear on Concentration Fluctuation Statistics in a Point Source Plume. Boundary-Layer Meteorol 129, 65–97 (2008). https://doi.org/10.1007/s10546-008-9305-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10546-008-9305-y