Effective urban square ventilation is important for the living comfort and health of residents. This research aims to establish some principles of street entry layouts for urban square ventilation optimization. Using computational fluid dynamics (CFD) simulation techniques, two types of street entry squares (two-intersection and four-intersection) were investigated under the effect of surrounding buildings. Three indices—the spatial mean velocity (<V*>), air change rate (ACH) and mean flow rates (<Q>) through the street entry and square roof—were calculated to quantify the square ventilation performance. The simulation results indicate that the surrounding buildings could influence the square space ventilation. When the surrounding building conditions change to a building coverage ratio of 0.25, the <Q> entering through the street entry can be reduced by 35%, and the <V*> within the square decreases by more than 45%. The optimal street entry layout design depends greatly on the wind direction. When the wind direction is perpendicular to the square street entry, the corner oblique-entry layout square shows a better ventilation performance than the other designs. When the wind direction is oblique to the square street entry, the <V*> declines greatly (up to 68%), and the lateral-entry layout design shows the best ventilation performance.

有效的城市广场通风对于居民的居住舒适和健康至关重要。本研究旨在为城市广场通风优化建立街道入口布局的一些原则。使用计算流体力学（CFD）模拟技术，在周围建筑物的影响下研究了两种类型的街道入口广场（两个交叉口和四个交叉口）。三个指标-空间平均速度（< V *>），换气率（ACH）和平均流速（< Q>）通过街道入口和方形屋顶进行计算，以量化方形通风性能。仿真结果表明，周围建筑物可能影响广场空间的通风。当周围的建筑条件更改为0.25的建筑覆盖率时，通过街道入口进入的< Q >可以减少35％，并且广场内的< V *>可以减少超过45％。最佳的街道入口布局设计在很大程度上取决于风向。当风向垂直于方形街道入口时，与其他设计相比，转角倾斜入口布局正方形显示出更好的通风性能。当风向倾斜于方形街道入口时，< V*>下降幅度最大（高达68％），横向入口布局设计显示出最佳的通风性能。