Numerical study of air pollution exposure in idealized urban street canyons: Porous and solid barriers

In this paper, it was considered the numerical modeling of concentration propagation using solid barriers and porous barriers of different heights in an idealized urban canyon to protect nearby houses. To solve this problem, a modification of the Reynolds-averaged Navier-Stokes equations was used to take into account the properties of the porous medium. To validate the mathematical model, a test problem was solved without taking into account various barriers. After validation, the main problem was solved, describing the process of pollutants emission between houses when using different types of vegetation barriers (solid and porous). All the obtained numerical results were compared with each other using different types of vegetation barriers. And the optimal porosity properties and permeability coefficient for vegetation barriers have been determined. So, from the obtained results, it can be noted that when using a solid green fence with a height of 0.1H, it was found that the concentration indicator significantly decreased compared to the results without barriers. But when comparing the indicators of the spread of the concentration with porous barriers after a height of 0.1H, a tendency to decrease in the maximum concentration is noticeable, but the average value of the concentration almost does not change.