基于流体力学的城市空间风热环境研究评述

Review on the Study of Urban Spatial Wind and Thermal Environment Based on Fluid Mechanics

摘要: 随着城市化的加快，城市人口的增多，城市内部产生人为热过量释放、空气污染、城市热岛效应等环境问题，城市空间风热环境逐渐恶化。因此，以流体力学为理论基础学科发展起来的城市空间风热环境的研究逐步增多。大量城市空间风热环境的研究都以流体力学为研究理论基础，因此，本文意在梳理流体力学在城市空间风热环境研究领域的应用过程与方式。首先，本文对城市空间风热环境研究中运用流体力学的原因进行简要分析。其次，本文对空气无穷小流体元在拉格朗日坐标系下x轴方向的受力进行了深入分析，从无穷小流体元与周围流体的速度关系出发，说明其受每个力的具体原因，y、z两个方向的受力同理。之后，推导了无穷小流体元在拉格朗日坐标系下的质量守恒、动量守恒与能量守恒方程。然后，本文对城市空间风热环境研究中的边界层与空气流体的流动状态进行了简要评述，包含边界层厚度的确定方法以及湍流模型的优缺点和选取方法。最后，将青岛理工大学嘉陵江东路校区北部宿舍生活区(以下均称北区宿舍)作为城市空间风热环境的研究应用实例，运用计算流体力学软件ANSYS进行计算流体力学模拟，仿真其风热环境，得到了北区宿舍风速场、温度场与风压场。

Abstract: With the acceleration of urbanization and the increase of urban population, environmental issues such as excessive anthropogenic heat release, air pollution, and urban heat island effects have emerged within cities, leading to the gradual deterioration of urban wind-thermal environments. Consequently, research on urban wind-thermal environments, developed based on fluid mechanics as the theoretical foundation, has progressively increased. Since a significant body of studies on urban wind-thermal environments relies on fluid mechanics as their theoretical basis, this paper aims to systematize the application processes and methodologies of fluid mechanics in this research domain. First, this paper briefly analyzes the rationale for employing fluid mechanics in urban wind-thermal environment studies. Second, it conducts an in-depth analysis of the forces acting on an infinitesimal air fluid element along the x-axis in a Lagrangian coordinate system, explaining the specific causes of each force based on the velocity relationship between the element and its surrounding fluid. Similar analyses apply to the y- and z-axis directions. Subsequently, the mass conservation, momentum conservation, and energy conservation equations for the infinitesimal fluid element in the Lagrangian framework are derived. The paper then provides a concise review of boundary layers and airflow states in urban wind-thermal environment research, including methods for determining boundary layer thickness, as well as the advantages, limitations, and selection criteria of turbulence models. Finally, the Northern District Dormitory Area of Qingdao University of Technology’s Jialingjiang East Road Campus (hereafter referred to as the Northern Dormitory Area) is examined as a case study. Computational fluid dynamics (CFD) simulations are performed using ANSYS software to model the wind-thermal environment, yielding detailed wind speed fields, temperature fields, and wind pressure fields for the Northern Dormitory Area.