NUMERICAL SIMULATION OF THE PROPAGATION OF A HARFULL EMISSIONS PASSIVE IMPURITY OVER A TWO-DIMENSIONAL MODEL OF THE TERRAIN

Abstract

High concentrations of pollutants are caused not only by strong emissions, but also by a decrease in dispersion, especially in the atmospheric layer adjacent to the surface, where most of the pollutants are emitted. In this paper, the forecast of wind flow and dispersion of pollutants over a two-dimensional hilly terrain is considered by numerical methods. The experimental data were used to verify the reliability of the numerical results of modeling the propagation of a passive impurity over a two-dimensional uneven terrain. The numerical data agree quite satisfactorily with the profiles of the average velocity and turbulence characteristics measured in the experiment. The hypothesis about the independence of the flow of the boundary layer of the atmosphere over an aerodynamically uneven terrain from the Reynolds number is confirmed by numerical methods. The influence of two-dimensional hills on the dispersion of pollutants from continuously or temporarily operating sources of different heights and locations of emissions is also studied. Concentrations of harmful impurities at the level of the earth's surface significantly decrease as the height of the source of their emissions increases. In addition, the numerical values of the concentration at ground level are somewhat overestimated. This is probably due to large deviations in the wind direction near the ground during the field experiment, which lead to a change in the direction of propagation and low concentrations of harmful emissions at ground level.