Dynamika proudění uvnitř městské křižovatky: charakteristiky šikmosti a špičatosti

The experiment uses wind-tunnel modeling method to investigate an intermittent ventilation of pollutants within an urban intersection and adjacent canyon. The skewness and kurtosis of velocity components were obtained in order to identify an area with strong intermittent tendency. Pollutants have released from line source and mean concentration was obtained using slow flame ionization detector. Vertical vortices as well as corner vortices are responsible for accumulation of emissions emitted by vehicle traffic. However, flow instabilities corresponding to enhancement of skewness can reduce or enhance the instantaneous level of exhalations. Vertical and horizontal momentum flux was analyzed by quadrant analysis. The method has detected the localities with highest momentum transfer from free stream down to the canyon. The connection between sweep and skewness in this area was found