CFD simulations of flow and dust dispersion in a realistic urban area

Fluid flow and dust transportation in a realistic urban residential community under dust storm weather conditions are investigated using computational fluid dynamics (CFD) with a grid resolution of several meters. The dust transportation and concentration distribution are obtained through the Lagrangian-formulated discrete particle model by integrating the particle velocity between certain time intervals. The fluid flow is solved by the realizable k - epsilon model. It is found that the dust transportation and distribution are very closely related to the flow field. The flow field in a real residential community is very complicated. When the building axes are perpendicular to the wind direction, the flows resemble the classic street canyon flow. Places with a low wind speed and high vorticity usually have a high dust concentration. As the wind direction changes, the fluid flow and dust distribution differ from case to case, but the general features are kept. In addition, the building shape and particle-wall interaction conditions have additional effects on the dust distribution, which need further study in the future.