Flow and Dispersion of Pollutants Over Two-Dimensional Hills: Summary Report on Joint Soviet-American Study

摘要

Wind tunnel experiments and theoretical models concerning the flow structure and pollutant diffusion over two-dimensional hills of varying aspect ratio are described and compared. Three hills were used, having small, medium and steep slopes. Measurements were made of mean and turbulent velocity fields upwind, over and downwind each of the hills. Concentration distributions were measured downwind of tracer sources placed at the upwind base, at the crest, and at the downwind base of each hill. These data were compared with the results of two mathematical models developed in the U.S.S.R. for treating flow and dispersion over two-dimensional hills. Measured concentration fields were reasonably well predicted by the models for a hill of small slope. The models were less successful for hills of steeper slope, because of flow separation from the lee side of the steepest hill and high turbulence and much-reduced mean velocity downwind of the hill of medium slope.