A FINITE ELEMENT MODEL FOR THE SIMULATION OF DENSE GAS DISPERSION IN THE ATMOSPHERE

✍ Scribed by A. I. Sayma; P. L. Betts

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 499 KB
• Volume: 24
• Category: Article
• ISSN: 0271-2091
• DOI: 10.1002/(sici)1097-0363(19970215)24:3<291::aid-fld495>3.0.co;2-#

✦ Synopsis

A state-of-the-art model is developed for the simulation of the dispersion of hazardous toxic or flammable gases heavier than air in the atmosphere. The model depends on solving the Reynolds-averaged Navier-Stokes equations in addition to the energy equation and a species concentration equation for the contaminant gas. Turbulence closure is achieved by using a buoyancy-extended version of the standard k-E two-equation model. The buoyancy extension is introduced to account for the anisotropic turbulent viscosity resulting from the strong stratification introduced by the dense gas clouds. The spatial discretization is achieved via the Galerkin finite element method, while the solution is advanced in time using the forward Euler method. A special element layer is introduced in the near-ground region to bridge the gap between the solid wall and the main solution domain where the turbulence model can be applied. This special element layer eliminates the need to apply the wall function in the standard way where any oscillations in the pressure field could contaminate the velocity solution. The model was tested against the Burro-8 field trial and could predict the experiment satisfactorily to within the experimental uncertainties of the reported results.