Dense-Gas Dispersion in Complex Terrain (PREPRINT)
Technical rept. 1 Oct 1990-31 Dec 1991
LAWRENCE LIVERMORE NATIONAL LAB CA
Pagination or Media Count:
A dense-gas version of the ADPIC Lagrangian particle, advection-diffusion model has been developed to simulate the atmospheric dispersion of denser-than-air releases over complex terrain. In developing the model, it was assumed that the dense-gas effects could be described in terms of the vertically-averaged thermodynamic properties and the local height of the cloud. The dense-gas effects were treated as a perturbation to the ambient thermodynamic properties density and temperature, ground level heat flux, turbulence level diffusivity, and windfield gravity flow within the local region of the dense-gas cloud. These perturbations were calculated from conservation of energy and conservation of momentum principles along with the ideal gas law equation of state for a mixture of gases. ADPIC, which is generally run in conjunction with a mass-conserving wind flow model to provide the advection field, contains all the dense-gas modifications within it. This feature provides the versatility of coupling the new dense-gas ADPIC with alternative wind flow models. The new dense-gas ADPIC has been used to simulate the atmospheric dispersion of ground-level, colder-than-ambient, denser-than-air releases and has compared favorably with the results of field-scale experiments.
- Atmospheric Physics