Transformation of a torch of a low source of, parasitic lets in conditions of the uniform or stratifiedwind flow

Abstract

In activi& the outcomes of numerical and physical simulation of distribution of a turbulent jet with parasitic impurity continuously which are flowing out from a source of a small altitude with the velocity VS in wind flow with the'velocity VH uniform, gradient or stratified flow are stated. For numerical calculation of flow the method of integral ratio was used. The outcomes of calculations of a position of a central axis of a gas plume for different values of number Richardson (Ri), describing thermal stratification of atmosphere are submitted. The physical simulation implemented in wind tunnel of a low speed of diameter 1,2 m and length of a working section 2,O m; The technique of simulation of a ground boundary layer for different types of a underlying surface is developed. The classification of the forms of plumes for different external conditions is carried out. The pictures of visualization are parsed and the experimental data on concentration "of marked gas" near to an earth surface are adduced. The satisfactory coincidence of the computational and experimental data is shown. Introduction Problem of protection of an environment, in particular of atmospheric air one of the major tasks of mankind. The main danger is represented by contamination of atmosphere by lets of industrial firms and power systems. The value of concentration of parasitic impurity in atmosphere in main is influenced with meteorological conditions, velocity of a wind, inversion of temperature. Therefore in the task of the forecast of carry and dispersion of impurity in air from continuous low sources, for example, pipes of chemical manufactures or smoke pipes of boiler-houses, it is important to know the possible forms of plumes and condition of their transformation (dispersion) in space. Generally atmospheric processes can be described by equations of the Navies-Stokes supplemented appropriate models of processes of turbulent carry [l]. However, as process in atmosphere uncontrollable also depend on large number factor to receive theoretical solution in general statement of the task predicament, At the numerical solution of the task it is important to give a qualitative and quantitative estimation of influence of parameters of a buoyancy, stratification and wind of a flow on basic performances of a jet which is flowing out from a point source of lets. In many difficult situations, whether it be difficult relief districts, industrial a complex or habitation microdistriet for obtaining information about a field concentration touch rationally to use physical modeling in wind tunnel. The situation nature experiment is nonconstant and there can not be reproduce at will. On of physical model, measuring manage much cheaper. Laboratory regulation of an air flow and boundary geometry allows to create systematically vary flows, in which it is possible realize fundamental researches dispersion of parasitic impurity and verification of numerical models. .