A microscale mathematical model of a non-isothermal turbulent flow and transport of a passive gaseous pollutant in a street canyon

This work is devoted to the description and testing of the developed numerical microscale mathematical model of a non-isothermal turbulent flow and transport of a passive gaseous pollutant in street canyons and city blocks. The model is successfully applied to consider three-dimensional turbulent steady flows in a wind tunnel with a heated groove and in a cavern channel with a pollutant supply, for which measurements are available. A comparison of the calculated results, experimental data, and calculations obtained using ANSYS Fluent demonstrates the validity of the numerical model. The model is used to calculate and analyze the fields of wind speed and pollutant concentration, as well as the integral characteristics of the pollutant concentration in a street canyon as a whole and in a breathing zone (up to 2 meters above the canyon bottom) with partial or overall heating of the windward wall of the canyon. The flow structure and the observed maximum and average concentrations of the pollutants are found to depend significantly on the size of the heated part of the windward canyon wall.