## 2 Methods
### Simulation and Solution  
CFD analysis was performed using a polyhedral mesh grid generated through ANSYS Meshing (Ansys-Fluent v22.2). Considering the change in outdoor wind direction, the inlet and outlet of wind speed in the geometric model will be changed, and the power shadow area has a large impact on the building surroundings, so the size of the calculation area has a significant impact on the accuracy of the numerical calculation results. If the computational domain is too small it will cause problems of flow field distortion and insufficient flow development, and if the computational domain is too large it will cause unnecessary waste of computational resources [23]. Regarding the setting of the computational domain, the COST guideline stipulates that for the simulation of a single building, the distance between the two sides of the building and the two sides of the computational domain should be more than 5 times the height of the building, the distance between the top of the building and the top boundary of the computational domain should be more than 5 times the height of the building, and the distance between the boundary of the air outlets and the building should be at least 15 times the height of the building. Based on the above considerations, the dimensions of the computational domain for the simulation in this study are set as shown in Figure 2. Taking the base model as an example, the distance of the wind speed inlet from the building is usually 5 H (H is the building height), the distance of the outlet from the building is 10 H, and the boundaries of the left and right calculation domains are usually 5 H from the building. Before conducting outdoor wind field calculations, it is essential to determine the size of the computational domain involved, termed the computational domain in fluid mechanics, which typically constitutes a rectangular or cubic space encompassing a cluster of buildings.  
Figure 2 displays a cross-sectional diagram of the wind field computational domain, the grid generation, and the allocation of boundary conditions for each region. The dimensions of the wind field are 317 m in length, 281 m in width, and 126 m in height. The total grid count amounts to 1,687,448.  
Figure 3 illustrates the research workflow of this study. Initially, the objective was to explore the potential of natural ventilation in reducing temperatures and conserving energy, coupled with geographical and climatic data for preliminary architectural design. Subsequently, from an architectural perspective, energy-saving considerations were incorporated, encompassing the preliminary design of ventilation corridors, architectural self-shading, and the augmentation of ventilation. Thirdly, an architectural model was established using simulation software, followed by the configuration of various parameters for simulation. Finally, the simulation results validated the substantial energy-saving effects of the architectural energy-saving methods considered during the initial design phase.  
Figure 2: Schematic diagram of CFD simulation and meshing (colours difference denoting computational domains for building surrounding zones and city wind environment respectively).