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Appendix 6: Representative Gas Cloud Models - TP 743 E
Previous Page | Table of Contents | Next Page
| Model Name | Technology Approach | Model Type |
|---|---|---|
|
Welker, et al. (1969) Ref: AGA (1973) |
Gaussian | Model assumes vapour cloud is neutrally buoyant. Release source is subdivided into a number of point sources. |
|
Drake, et al. (1969) Ref: AGA (1973) |
Gaussian | Model assumes vapour cloud is neutrally buoyant. Release source is converted to a line source and then a virtual point source. |
|
Germeles-Drake (1973) Ref: Germeles and Drake (1975) |
Gravity Dispersion followed by Gaussian | Model initially assumes vapour cloud is heavier than air and spreads due to the density differences between the cloud and the surrounding air. At a selected cloud density or lateral velocity, gravity dispersion is terminated and Gaussian initiated. |
|
SIGMET (SAI) (1975) Ref: Havens (1979) |
Transport | Models cloud dispersion using mass and momentum transport equations. A total of six partial differential equations must be solved. There are a number of constants that must be selected. |
|
Eidsvik (1979) Ref: Eidsvik (1980) |
Gravity Dispersion followed by Gaussian | Eidsvik is similar to Germeles-Drake but improves the air / cloud transport mixing portion of the model during gravity dispersion. |
|
HEGADAS (1980) Ref: Colenbrander (1980) |
Gravity Dispersion | Similar to Eidsvik and Germeles-Drake. Primary difference is that during gravity spread phase, cloud cross section profile is better modeled. |
|
ZEPHER (1981) Ref: Woodward, et al. (1981) |
Transport | Same as SIGMET except for mathematical solution procedures. |
|
MARIAH (1981) Ref: Woodward, et al. (1981) |
Transport | Same as SIGMET except for mathematical solution procedures. |
| Safeti (1986) | Combination | A "standard box" model with numerous enhancements to the initial cloud development. |
|
Robinson, et al. (1988) Ref: NOAA (1988) |
Transport and Gaussian Dispersion | Estimates pollutant concentrations downwind from the source, taking into account the toxicological and physical characteristics of the spilled material. |
