Abstract A macroscopic zone model is used to analyze buoyancy-driven natural ventilation in one storey connected with an atrium. The height ratio between the storey and atrium can be variable as well as the heat ratio between the two heat sources, one in storey and the other in atrium. Both the steady-state and time-dependent flow rate through the storey and atrium are investigated. The transient process from different initial conditions to different steady-state flow patterns are numerically performed by means of Euler method, especially the detailed investigation of time evolution of flow rate between different flow patterns from ‘zero’ initial conditions. Seven classical cases of time development flow rate are given to explain flow pattern can evolve from one to another and the implications of natural ventilation driven by the two opposing buoyancy forces in atrium building are discussed. Furthermore, small-scale experiments were conducted to evaluate switch of flow pattern in transient flow. Stability analysis and bifurcation point of multiple flow patterns are also considered on the basis of fundamental nonlinear dynamics.

中文翻译：

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一层与中庭相连的浮力驱动自然通风

摘要 宏观区域模型用于分析与中庭相连的一层中浮力驱动的自然通风。楼层和中庭之间的高度比以及两个热源（一个在楼层，另一个在中庭）之间的热比可以是可变的。研究了通过楼层和中庭的稳态和随时间变化的流速。从不同的初始条件到不同稳态流型的瞬态过程通过欧拉方法进行了数值计算，特别是从“零”初始条件下不同流型之间流速的时间演化的详细研究。给出了七个时间发展流速的经典案例来解释流动模式可以从一种演变为另一种，并讨论了中庭建筑中由两种相反的浮力驱动的自然通风的影响。此外，还进行了小规模实验以评估瞬态流中流型的转换。在基本非线性动力学的基础上，还考虑了多种流型的稳定性分析和分岔点。