Modelling of Atmospheric Flow and Dispersion in the Wake of a Cylindrical Obstacle

This paper presents computational simulations of atmospheric dispersion experiments conducted around isolated obstacles in the field. The computational tool used for the simulations was the code ADREA-HF, which was especially developed for the simulation of the dispersion of positively or negatively buoyant gases in complicated geometries. The field experiments simulated involve a single cylindrical obstacle normal to the mean wind direction and two upwind sources of ammonia and propane, with the ammonia source located at different lateral positions (Mavroidis et al., 2003). Concentrations and concentration fluctuations for both gases were calculated by the model and compared with the experimental results to evaluate the model performance. Specific characteristics of dispersion were investigated using the computational tool. Comparisons of experimental and model results with the case of dispersion around an isolated cubical obstacle are also presented and discussed.