Plume models

Gaussian mode Gaussian plume model Gauss-Seidel Gauzes Gaylusite... 

Atmospheric stabUity can be examined utilising the Gaussian Plume model which ignores possible transformations ... 

N. E. Bowne, R. J. Londergan, R. J. Minott, D. R. Murray, "Preliminary Results from the EPRI Plume Model VaUdafion Project— Plains Site,"... 

Gaussian Plume Model. One of the most basic and widely used transport models based on equation 5 is the Gaussian plume model. 

Gaussian plume models for continuous sources can be obtained from statistical arguments or can be derived by solving ... 

Gaussian plume models are easy to use and require relatively few input data. Multiple sources are treated by superimposing the calculated contributions of individual sources. It is possible to include the first-order chemical decay of pollutant species within the Gaussian plume framework. For chemically, meteorologically, or geographically complex situations, however, the Gaussian plume model fails to provide an acceptable solution. 

FIG. 26-54 Horizontal dispersion coefficient for Pasquill-Gifford plume model, Reprinted ffomD. A. Ct owl and J. F. Louvar, Chemical Process Safety, Fundamentals with Applications, Z.9.90, p. 138. Used hy permission of Ft entice Hall)... 

The plume model describes continuous release of material. The solution depends on the rate of release, the atmospheric conditions, the height of the release above ground, and the distance from the release. In this case, the wind is moving at a constant speed u in the x direction. The equation for the average concentration for this case is (Crowl and Louvar, 1990, p. 142) ... 

Pasquill, F., "Atmospheric Ehspersion Parameters in Gaussian Plume Modeling, Part II. Possible Requirements for Change in the Turner Workbook Values," EPA-600/4-76-030b. U.S. Environmental Protection Agency, Research Triangle Park, NC, 1976. 

Electric Power Research InsHtute, "Preliminary Results from the EPRI Plume Model Validation Project—Plains Site." EPRI EA-1788, RP 1616. Palo Alto, CA. Interim Report. Prepared by TRC Environmental Consultants, 1981. 

Electric Power Research Institute, "Survey of Plume Models for Atmospheric Application," Report No. EPRI EA-2243. System Application, Inc., Palo Alto, CA, 1982. 

Air Pollution Dispersion Application of air dispersion modeling principles and EPA tools to assessing environmental impacts from stack and area releases of pollutants Dispersion theory Gaussian plume model Ground-level concentrations Worst case scenarios Air quality impact assessments Stationary source emissions... 

The earliest and still widely used dispersion model to compute pollutant concentration profiles is the Gaussian plume model for single or multiple source pollution problems. Box-type model techniques, which can take into account nonlinear interactions among different species arising from chemical reactions, have been used in longer-range dispersion computations. 

The Gaussian Plume Model is the most well-known and simplest scheme to estimate atmospheric dispersion. This is a mathematical model which has been formulated on the assumption that horizontal advection is balanced by vertical and transverse turbulent diffusion and terms arising from creation of depletion of species i by various internal sources or sinks. In the wind-oriented coordinate system, the conservation of species mass equation takes the following form ... 

Figure 11. Coordinate systems for Gaussian plume model.

Using the Gaussian plume model and the other relations presented, it is possible to compute ground level concentrations C, at any receptor point (Xq, in the region resulting from each of the isolated sources in the emission inventory. Since Equation (2) is linear for zero or linear decay terms, superposition of solutions applies. The concentration distribution is available by computing the values of C, at various receptors and summing over all sources. 

Software for dispersion modeling uses Gaussian plume model. Phe system calculates concentration or deposition values for inputed time periods. May be used in conjunction with "Breeze Air."... 

The straight-line plume model is not used instead the model computes the trajectory of each segment of the plume as the wind changes with time. The actual terrain is modeled for the region within about nine miles of the plant. 

The jet-plume model only simulates vertical jets. Terrain is assumed to be flat and unobstructed. Application is limited to surface roughness mush less than the dispersing layer. User experti.se is required to ensure that the selected runtime options are self-consistent and actually reflect the physical release conditions. Documentation needs improvement there is little guidance... 

RTDM (Rough Terrain Diffusion Model) is a sequential Gaussian plume model designed to estimate ground-level concentrations in rough (or flat) terrain in die vicinity of one or more co-located point sources. 

The modeling package, delivered to the EPA, includes nationwide data bases for emissions, dispersion meteorology, and population patterns. These data are used as input for a Gaussian plume model for point sources and a box model for urbanwide area sources. Prototype modeling is used for point sources that are too numerous to define individually. Building wake effects and atmospheric chemical decay are addressed. 

Two types of neutrally buoyant vapor cloud dispersion models are commonly used the plume and the puff models. The plume model describes the steady-state concentration of material released from a continuous source. The puff model describes the temporal concentration of material from a single release of a fixed amount of material. The distinction between the two... 

The puff model can be used to describe a plume a plume is simply the release of continuous puffs. However, if steady-state plume information is all that is required, the plume model is recommended because it is easier to use. For studies involving dynamic plumes (for instance, the effect on a plume of a change in wind direction), the puff model must be used. 

Figure 5-10 Dispersion coefficients for Pasquili-Gifford plume model for rural releases.

Figure 5-11 Dispersion coefficients for Pasquill-Gifford plume model for urban releases.

Pasquill-Gifford plume model At a given downwind distance x, the maximum (average) concentration for a (continuous) passive plume from a point source is... 

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