The CFD simulations used periodic flow boundary conditions in the east and west surfaces, which meant that the houses repeat indefinitely in the east and west directions. The results show that the air velocity at the houses in the downstream rows is much lower than at the upstream rows. However, the velocity stabilizes at the fourth row of houses and beyond, as shown in Fig. 5. This investigation used a house in the fifth row as a reference, since it can be regarded as a typical house in a large housing project.