A Modified Turbulent Energy Model for Diffusion from Elevated and Ground Point Sources in Neutral Boundary Layers

A simple model for turbulent diffusion is proposed based on a turbulent energy model modified by Galperin and Hassid (1986) wherein local equilibrium in the concentration flux equation is assumed resulting in a turbulent diffusivity tensor. The early stage of plume development is simulated through adjustment of the integral length scale of diffusion. A simple semi-empirical formulation is also proposed for the dissipation length scale of concentration variance. Although it is substantially simpler than that of Sykes et al. (1984), the model is shown to compare well with the measurements of Fackrell and Robins (1982a, b).