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).