Turbulent dispersion in a stable layer with a quadratic exchange coefficient

Abstract

Dispersion from a line source into a stable boundary layer of thickness I is analysed through solution of the diffusion equation assuming an exchange coefficient K(z) cc (1 -z/l)2 and wind profiles u(z) cc z", with n = 0, 1. Estimates of ground-level concentrations are made by developing analytic formulae where this is possible. A general method of solution using Laplace transformation and Green's function techniques is developed as an alternative to the eigenftmction expansion method discussed previously (Robson, 1983).

Time dependent mathematical model of air pollutants emitted from time-dependent elevated line source into a stable atmospheric boundary layer

“…Whereas in this model, the multiple Laplace transform inverted analytically this gives an exact solution. The solutions of this model verified with that of (Robson, 1987) by assuming no delayed removal (chemical reaction rate) and time independent case. It is interesting to note that the effect of chemical reaction rte has virtually no impact t the short travel time but has significant effect t large travel time.…”

“…In most of the previous models, numerical methods used either fully or partly. In model where the Laplace transform is generally inverted numerically (Robson, 1987). Whereas in this model, the multiple Laplace transform inverted analytically this gives an exact solution.…”

“…The step-function type of line sources were assumed the series of industries or highways on during certain period of time and not continuous. The results were validated by comparing that of Robson (1987) by chemically nonreactive and time independent case. It is interesting to note that when there is no chemical reaction of primary pollutants, the results of the present model coincide with the results of the model presented by Robson (1987).…”

“…The results were validated by comparing that of Robson (1987) by chemically nonreactive and time independent case. It is interesting to note that when there is no chemical reaction of primary pollutants, the results of the present model coincide with the results of the model presented by Robson (1987). This paper analyzed unsteady state dispersion of pollutants from a line source into stable atmosphere boundary layer.…”

Unsteady state mathematical model of chemically reactive pollutants from an instantaneous line source into a stable atmospheric boundary layer

“…The possibility of leakage of pollutants through inversion layer in negligibly less. Therefore, the diffusion coefficient of quadratic in nature considered which is best suited for the stable ABL (Robson [2]) in this model. The height of the atmospheric boundary layer is assumed to be z = H, from the surface.…”