A new Lagrangian stochastic model for the gravity-slumping/spreading motion of a dense gas

A new dispersion model for dense gas which is released into the atmosphere on the flat terrain is constructed within the Lagrangian framework. Using the hydrostatic assumption for pressure distribution within cloud due to density variation, slumping motion is successfully incorporated into the Lagrangian model with entrainment effect naturally considered. Turbulence suppression due to stable stratification within cloud is also taken into consideration in the model formulation. Various results including time variant and maximum concentration predictions by the proposed model are compared with the available measured data in the experiment conducted in Thorney Island in 1984 with good agreement.