NUMERICAL-SIMULATION OF HEAVY GAS CLOUD DISPERSION WITHIN TOPOGRAPHICALLY COMPLEX TERRAIN

Numerical analysis has been performed for predicting the dispersion of heavy gas clouds released without initial momentum (i.e. dense gas pu ffs) within regions of complex topography. The three-dimensional non-s teady differential equations governing transport are solved by means o f the numerical finite volume method, using a collocated variable arra ngement with a fully implicit integration over time. The turbulence ef fects on the flow properties are simulated by the two-equation k-epsil on turbulence model. Comparisons between calculated and measured data are presented, showing good agreement between them. The method is also used to predict a chlorine release within a fictitious industrial pla nt. The location of the release site, the atmospheric stability class and the wind direction are varied, in order to show the effect of topo graphy on the cloud dispersion.