1994 Volume 29 Issue 6 Pages 297-312
In recent years, high-order turbulent statistics such as the second and higher moments of wind fluctuations, turbulent dissipation rate, and time scale have been often used to predict concentration distributions. Thispaper describes atmospheric dispersion models using high-order turbulent statistics, with special focus on the Lagrangian particle dispersion models. The Lagrangian particle dispersion models have the following features:
(1) The models are applicable to the analyses of diffusion phenomena in complicated flow fields generated by topography, heat and plants.
(2) The concept of the Lagrangian method is natural and easily understandable. Unlike the Eulerian model, the procedure of numerical solution is almost free of problems.
(3) A relatively small amount of work is required to establish the Lagrangian particle dispersion models compared with closure models.
Lagrangian particle dispersion models have been studied for nearly twenty-five years. During this period, the models have been developed to take consideration of the inhomogeneous and non-Gaussian turbulence. These models have been used successfully in the prediction of plume in the convective boundary layer. The models are expected to be useful in the prediction of the three-dimensional diffusion in a complex terrain, the diffusion analysis within a plant canopy or an urban canopy, and the prediction of concentration fluctuations
