Gallery 2 

Pic. 13. Cross section of plume at wind speed 2 m/s. Pic. 14. Influence of heat island upon plume rise. Pic. 15. Following four pictures depict horizontal NOx concentration field at various heights under various wind speeds, and also influence of heat island upon concentration fields structure. Pic. 16.
Pic. 17. Pic. 18. Pic. 19. Next 15 pictures reflect results, obtained in framework of project on PHOENICS validation. Here model validation was made on date of measurment of passive contaminant dispersion and flow parameters within idealized city model, obtained in a windtunnel. Model buildings represented various side bricks. Bricks were arranged as rows so as the distance between them was equal 5 sm. Bricks had equal width and height 5 sm, and their lenght was varied from 5 to 15 sm. Buildings were always arranged a longer side across the main stream of the air. Neutral boundary layer was modelled within the windtunnel. Source of substance represented ground level area one, placed between buildings rows, spreaded across main stream of the air. Full square of the source was equal 5x175 sm2. In this picture depicted airflow pattern behind buildings, obtained with help of k-l and k-e turbulent model at cube configuration of bricks 5x5x5. Pic. 20. Airflow fields obtained with help of k-l model and model with constant eddy viscosity coefficient. Here and further results of calculations series are presented, in which in front of the source 8 buildings rows were placed. It was necessary to get steady flow. In lateral direction also was set from 8 to 10 buildings rows, depending upon bricks lenght.
Pic. 21. Comparison of ground level concentrations fields, obtained by means of k-l and k-e turbulent models (the top view). Pic. 22. Comparison of ground level concentrations fields, obtained by means of k-l model and model with constant eddy viscosity coefficient (the top view). Pic. 23. Airflow fields behind the buildings, obtained by means of four various turbulent models under 10x5x5 brick configuration. Pic. 24. Comparison of ground level concentrations fields, obtained by means of k-l and k-e turbulent models under 10x5x5 brick configuration (the top view).
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