Numerical investigation on the effect of building overhang on the flow within idealised two-dimensional street canyon / Muhammad Fatih Ibrahim …[et al.]

Building overhang is an essential element in the construction of terrace houses in Malaysia to protect occupants from the sunlight, car parking, and social event purposes. However, there is still a lack of study investigating the effect of overhang in a windy area of terrace houses despite its effect on the flow modification around the building. Therefore, in this paper, a series of computational fluid dynamics (CFD) simulations were performed using Reynolds Average Navier Stokes(RANS) equations and renormalization group (RNG) k – ε as the turbulence closure model. Simulations were conducted on a unity aspect ratio of two-dimensional street canyon representing the low-rise terrace house area in a flat roof shape and three different overhang conditions. The protruding overhangs were significantly modified the in-canyon flow structure as it limited the penetration of the above flow into the canyon as compared to the without overhang case. In addition, spatially-averaged ? of the turbulent kinetic energy depicted that the value decreased within the canyon, demonstrating the independence of the overhang location. It is recommended to perform a further study on the ventilation performance of the street canyon through evaluation of ventilation indices such as ventilation rate, air exchange rate (ACH), and pollutant exchange rate (PCH).