000004629 001__ 4629 000004629 005__ 20141119144540.0 000004629 04107 $$aeng 000004629 046__ $$k2002-06-02 000004629 100__ $$aLai, Natalia T.N. 000004629 24500 $$aPOLLUTANT DISPERSION BY A TURBULENT WIND FLOW NEAR A LOW HILL 000004629 24630 $$n15.$$pProceedings of the 15th ASCE Engineering Mechanics Division Conference 000004629 260__ $$bColumbia University in the City of New York 000004629 506__ $$arestricted 000004629 520__ $$2eng$$aA methodology is developed to study the pollutant concentration distribution in a turbulent shear flow over a two dimensional hill with small slope. As in a typical boundary layer problem, the flow domain is divided into an inner and an outer region: the inviscid outer region is subdivided into an upper and a middle layer, while the viscous inner region consists of a shear stress and an inner surface layer. With the velocities obtained from the Navier-Stokes and continuity equations, the diffusion equation for the pollutant concentration is readily solved. A variational method with adjustments to the streamline coordinate system is used in order to obtain an accurate solution of the concentration in the downwind region. Closed form analytical solutions of the pollutant dispersion patterns and concentration distributions are determined. It is shown that when there is an upwind source located at the upper layer, the concentrations decrease with distance along the upwind side of the hill and tend to be a constant rapidly near the hilltop. As the eddy diffusivity increases, the concentrations become saturated at an earlier position. This diffusion model can be applied to any realistic flow field once the streamlines can be specified through the velocities. 000004629 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb. 000004629 653__ $$aStreamline coordinate system, Variational method 000004629 7112_ $$a15th ASCE Engineering Mechanics Division Conference$$cNew York (US)$$d2002-06-02 / 2002-06-05$$gEM2002 000004629 720__ $$aLai, Natalia T.N.$$iChan, Andy T. 000004629 8560_ $$ffischerc@itam.cas.cz 000004629 8564_ $$s175771$$uhttp://invenio.itam.cas.cz/record/4629/files/085.pdf$$yOriginal version of the author's contribution as presented on CD, . 000004629 962__ $$r4594 000004629 980__ $$aPAPER