Analysis and modeling on thermal and aero-dynamical forcing effect brought by urban canopy.

我们在上一个项目中开发了一套完整的直接测量系统，用于测量作用在建筑块区域上的阻力和来自城市树冠的标量通量传递。我们进行了系统和全面的风洞实验，以确定各种城市几何环境下的所谓的大阻力（动量）传递系数和大阻力标量传递系数。我们确定了一个良好的第一步开始，只要我们选择适当的参数，就可以获得城市几何中两个体积传递系数的某种普遍关系。我们发现，除了建筑密度外，每个建筑块体的长细、高度变化、阵列随机性都是影响城市冠层湍流结构传递系数的关键因素。除了风力实验，我们还采用了其他方法；PIV技术和CFD技术可以确保研究城市冠层内部和上方湍流结构的真实情况。LES是最先进的CFD技术之一，它揭示了与冠层内部动力学相关的冠层上方湍流组织结构（TOS）对热动力和气动强迫效应有显著影响。

The complete set of elaborated direct measurement systems for both drag force acting on a building blocks area and scalar flux transfer from urban canopies, which we developed in the previous project, systematic and comprehensive wind tunnel experiments to identify the so-called Bulk Drag (Momentum) Transferring Coefficient & Bulk Drag Scalar Transferring Coefficient for various urban geometric contexts were carried out. We identified a good first-step inception to get somehow universal relations of both two bulk transferring coefficients with urban geometry as long as we choose appropriate parameters. We grasped that not only building density but also slenderness of each building blocks as well as height variation, array randomness are crucially affecting on the transferring coefficients through turbulent structure brought by urban canopies. We also took other methodologies than the wind experiment; PIV technique and CFD that make sure to investigate what is really happening in and just-above urban canopies in terms of turbulent structure. LES, one of up-most CFD techniques, reveals that TOS (turbulent organized structure) emerged above canopies in connection with dynamics within canopies significantly affects onthe thermal and aero-dynamical forcing effect.