Numerical simulation of urban ventilation with different building scales

The past half century has seen an unprecedented growth of the world´s urban population. Increasing urbanization and concern about sustainability and quality of life issues have produced considerable interest in air quality in urban areas. Urban ventilation implies that rural areas may supply relatively clean air into urban canopies and distribute rural air within them to help air exchange and pollutant dilution. This paper numerically studied rural air flow through square building arrays at different wind angles. The building area density ( λ_p , i.e. the rario between the plan area of buildings viewed from above and the total underlying surface area) is restricted to 0.25, while the building numbers in the square region change from 9 to 81. A two-dimensional (2D) k-ε turbulence model is employed to solve the Reynolds-averaged Navier-Stokes equations.The model is employed to predict the influence of the building numbers on flow capacity in wind angle altering from 0° - 45°. 3D model is employed to solve this problem as well. It´s confirmed that fewer buildings get better flow capacity. Smaller wind angle improves this process as well.