Further assessment of FEM3: a numerical model for the dispersion of heavy gases over complex terrain

FEM3 is a three-dimensional numerical model for simulating the atmospheric dispersion of heavy gases over complex terrain. During the past few years, FEM3 has been assessed, using data from the Burro and Coyote series of LNG spill experiments conducted by LLNL at China Lake, California. In general, the model has been found to perform very well and it greatly complements the field experiments in enhancing our understanding of the phenomena associated with LNG vapor dispersion, including gravity spreading, heating from the ground surface, and terrain effects. In this paper, the FEM3 model is further applied to simulate the dispersion of nitrogen dioxide (NO/sub 2/) for one of the LLNL conducted nitrogen tetroxide (N/sub 2/O/sub 4/) spill tests and also to simulate the dispersion of propane gas for four of the refrigerated liquid propane spills conducted by SHELL Research Limited at Maplin Sands. The main purpose of the NO/sub 2/ simulation is to demonstrate the heavy gas effects in this test and the latter simulations are for assessing the performance of the current model for simulating the dispersion of propane gas. 12 refs., 12 figs.