A numerical simulation of dispersion from an elevated point source in the convective planetary boundary layer

Lamb, Robert G.

doi:10.1016/0004-6981(78)90068-9

Cited by 153 publications

(58 citation statements)

References 8 publications

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“…2(a), the descending plume intercepts the ground at a distance of about 1.5 z i U/w * . This agrees well with Lamb's (1978) simulation, but in Enger's (1986) simulation the interception took place at 1.9 z i U/w * . Also in this case the present model results show a rise of the plume after it reaches the surface.…”

Section: Model Validationsupporting

confidence: 88%

“…After a distance of 6 z i U/w * the concentration is well mixed within the entire CBL with concentrations of about 0.95. The results are in very good agreement with those from the tank experiments by Willis and Deardorff (1978), with the Lagrangian model simulation by Lamb (1978) and with the Eulerian model simulation by Enger (1986). In their results, the maximum centre-line concentration intercepts the ground at 0.4, 0.6, and 0.5 z i U/w * , respectively.…”

Section: Model Validationsupporting

confidence: 86%

“…A characteristic of an elevated-source diffusion regime in a CBL is that, beginning near the source, the plume centre-line, as defined by the locus of the maximum concentration, descends until it reaches the ground. This phenomenon was first pointed out by Lamb (1978). By contrast, material released by a surface source first moves horizontally after which it starts to ascend.…”

Section: Introductionmentioning

confidence: 93%

“…Nevertheless, the Eulerian model is able to simulate the characteristics of dispersion from point sources in the CBL (Enger 1986(Enger , 1990b. This means that there must exist an explanation for the plume behaviour other than the one argued by Lamb (1982), see above. The aim of the present study is, therefore, to examine the role of advection and diffusion of the fluxes on modelling dispersion in CBLs.…”

Section: Introductionmentioning

confidence: 95%

“…The resolvable-scale components of wind velocity are obtained directly from the mesoscale meteorological model, and turbulent components are generated with the aid of, for example, a Markov chain scheme or a fully random walk scheme. Examples of such models are described in Lamb (1979) and Uliasz (1994). Application of large-eddy simulation (LES) models to study the behaviour of passive and buoyant plumes in the convective boundary layer (CBL) has also been reported by Nieuwstadt and de Valk (1987), van Haren and Nieuwstadt (1989), Sykes and Henn (1992) and Henn and Sykes (1992).…”

Section: Introductionmentioning

confidence: 97%

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The role of advection of fluxes in modelling dispersion in convective boundary layers

Abiodun

Enger

2002

Quart J Royal Meteoro Soc

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SUMMARYA Eulerian three-dimensional higher-order closure dispersion model is presented. The model uses mean wind and turbulence quantities from a second-order atmospheric boundary-layer model. The dispersion model is validated against results from tank and field experiments and compared to results from Lagrangian dispersion models. The results show quite good agreement with experiment and Lagrangian modelling results for point source dispersion in a convective boundary layer (CBL). Sensitivity studies with the model help to identify the role played by advection and horizontal transport terms in the equations for the fluxes in simulating the essential features of pollutant dispersion.Results from the sensitivity tests show that the characteristic features of dispersion from point sources in the CBL-with an ascending plume during ground-level release and a descending plume from a lifted point source-are caused by an imbalance between the advection and diffusion terms in the equation for the vertical flux. Furthermore, it is shown that there is also a tendency for the plume to split horizontally, which is similarly caused by an imbalance between the advection and diffusion terms in horizontal fluxes. The simulated lateral standard deviations of distance x from a point source, for the vertically integrated concentration, are proportional to x close to the source and to x 1/2 far away from the source, if and only if the advection and diffusion terms are included in the equations for the turbulent fluxes of concentration.

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Section: Model Validationsupporting

confidence: 88%

Section: Model Validationsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 97%

See 3 more Smart Citations

The role of advection of fluxes in modelling dispersion in convective boundary layers

Abiodun

Enger

2002

Quart J Royal Meteoro Soc

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Parallel computation of atmospheric pollutant dispersion under unstably stratified atmosphere

Liu

Leung

1998

Int. J. Numer. Meth. Fluids

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Gaussian Dispersion Modeling

Visscher

2013

Air Dispersion Modeling

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In the studies of fate and transport of air emissions from animal feeding operations, Gaussian based dispersion models have been commonly used to predict downwind pollutant concentrations through forward modeling approach, or to derive emission rates and emission factors through inverse dispersion modeling approach. In the Gaussian dispersion modeling process, downwind sampling location and sampling height could generate significant impact on accuracy of the model validation, or inverse modeling results based upon field measurements. This study theoretically analyzed the impact of downwind locations and sampling height on Gaussian dispersion modeling. It was discovered that the field sampling needs to be conducted at the locations beyond the plume touching-ground distance, at a downwind distance as short as 5 m for the case scenario with zero rise of emission plume under the atmospheric stability class C, or as long as 297 m for the case scenario with 15 m rise of emission plume under the atmospheric stability class F. In order to measure the PM concentrations of the dispersion plume, the minimum sampling height at the locations within the plume touching-ground distance varied from ground level to as high as almost 14 m, whereas for the locations beyond the plume touching-ground distance, a sampling height of ground level would be acceptable.

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A numerical simulation of dispersion from an elevated point source in the convective planetary boundary layer

Cited by 153 publications

References 8 publications

The role of advection of fluxes in modelling dispersion in convective boundary layers

The role of advection of fluxes in modelling dispersion in convective boundary layers

Parallel computation of atmospheric pollutant dispersion under unstably stratified atmosphere

Gaussian Dispersion Modeling

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