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Main Title Turbulent Diffusion from a Point Source in Stratified and Neutral Flows around a Three-Dimensional Hill. 2. Laboratory Measurements of Surface Concentrations.
Author Snyder, W. H. ; Hunt, J. C. R. ;
CORP Author Environmental Sciences Research Lab., Research Triangle Park, NC. Meteorology and Assessment Div. ;Cambridge Univ. (England). Dept. of Applied Mathematics and Theoretical Physics.
Year Published 1984
Report Number EPA/600/J-84/158;
Stock Number PB85-148401
Additional Subjects Air pollution ; Turbulent flow ; Mathematical models ; Hills ; Plumes ; Laboratory equipment ; Concentration(Composition) ; Wind tunnels ; Test chambers ; Reprints ; Atmospheric dispersion ; Three-dimensional calculations ; Foreign technology
Library Call Number Additional Info Location Last
NTIS  PB85-148401 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 37p
Towing-tank and wind-tunnel measurements of the concentration distributions on the surface of a hill when a plume impinges from an upwind source are presented. The stability is varied between very stable and neutral. The results are compared with the theories developed in Part I. When the source is below the dividing-streamline height HD, the plumes impact on the front surface of the hill, yielding surface concentrations nearly the same as would be observed at the plume centerline in the absence of the hill. However, eddying in the wake can cause oscillations in the plume upwind so as to increase the area of impingement and decrease the average concentration. When the source is above HD, the plume surmounts the hill top, but if it is only slightly above HD, maximum surface concentrations can again essentially equal those that would be observed at the plume centerline in the absence of the hill. The maximum surface concentration decreases very rapidly with further increases in source height. The location and value of the maximum surface concentrations are found to be extremely sensitive to slight displacements of the source from the stagnation streamline when the source is below HD. The potential flow models developed in Part I provide reasonable estimates of surface concentrations on three-dimensional hills.