Accurate CFD Modeling of Atmospheric Boundary Layer with an Emphasis on Wind-Induced Response of Buildings

设计规范在建筑物的风荷载评估方面有几个局限性，可以通过使用风洞WT测试或计算流体动力学CFD模拟来克服。风洞测试通常需要较长的模型构建和仪器准备时间（几周/几个月），如果使用并行计算能力，则CFD不会出现这种情况。正确地模拟大气边界层（BL）是准确的CFD模拟的关键。本研究的重点是评估和提高CFD中两种边界层生成方法（即分形表面粗糙度方法和一致随机离散流生成CDRFG方法）的精度，以评估高层建筑的风致荷载和响应。 首先，将两种选定的BL生成方法合并到Ryerson U提供的ANSYS FLUENT和Open Foam软件中，并由RWDI常用。然后，将进行几次模拟，以找到导致使用空域精确模拟BL的参数（及其范围）。一旦确定了这些参数（及其范围），模拟将扩展到包括具有和不具有周围配置的建筑物，以评估风致荷载和响应，这将根据Ryerson和RWDI的WT实验进行验证。 本研究项目的预期成果代表了使用CFD的湍流BL的两种精确建模方法。这些方法将使RWDI能够以更低的成本更快地进行风力工程研究，同时保持准确性。这不仅对RWDI，而且对加拿大都有很大的好处，因为由此产生的方法最终将导致更有弹性的建筑物，以应对气候变化经常导致的风相关灾害，这是加拿大政府的优先研究领域。

Design codes have several limitations when it comes to wind load evaluation of buildings, which can be overcome by using Wind Tunnel WT testing or Computational Fluid Dynamic CFD simulations. Wind Tunnel testing typically requires a long lead time (several weeks/months) for the model construction and instrumentation, which is not the case for CFD if the parallel computational power is utilized. It is essential for an accurate CFD simulations to properly model the atmospheric Boundary Layer (BL). This proposal focuses on assessing and enhancing the accuracy of two of BL-generating methods in CFD (namely the fractal surface roughness method and the Consistent Random Discrete Flow Generation CDRFG method) to evaluate wind-induced loads and responses of tall buildings. First the two selected BL-generating methods will be incorporated on ANSYS FLUENT and Open Foam software available at Ryerson U and commonly used by RWDI. Then, several simulations will be conducted to find the parameters (and their ranges) leading to accurate simulation of BLs using empty domains. Once those parameters (and their ranges) are identified, the simulations will be extended to include buildings with and without surrounding configurations to evaluate wind-induced loads and responses, which will be validated against WT experiments at Ryerson and RWDI. The anticipated outcomes of this research project represent two accurate modeling methods for turbulent BLs using CFD. Those methods will enable RWDI to conduct wind engineering studies faster, at a lower cost while maintaining the accuracy. This will be of a great benefit to not only to RWDI, but also to Canada as the resulting methods will ultimately lead to more resilient buildings to wind-related disasters frequently driven by the climate change, which is a priority research area for the Canadian Government.