高层建筑周边三维瞬态风场的混合数值模拟

Hybrid simulation of three dimensional fluctuating wind fields around tall buildings

为了改进高层建筑周边瞬态风场数值模拟方法的计算效率,在随机流场生成方法和计算流体动力学(CFD)的基础上提出高效的混合型数值模拟方法.采用雷诺应力模型求解标准高层建筑模型(CAARC)周边的时均化湍流场,结合获得的雷诺应力张量修正瞬态风场的风功率谱.运用随机流场生成方法和快速傅里叶变换技术模拟得到该建筑周边的三维脉动风速场.以谱密度函数、互相关函数以及空间相关系数为特征指标量,对风速场模拟样本的物理和数值特征进行验证.研究表明:计算得到的风场满足流体不可压缩条件,与传统模拟方法的结果相比更符合风谱能量分布等真实大气湍流物理特征,证明提出的瞬态风场混合模拟方法可以高效准确的求解受建筑干扰后的真实三维脉动风速场.

A computationally efficient hybrid simulation method was developed by combining random flow generation technique and the computational fluid dynamics （CFD） method. Reynolds stress turbulence model was employed to calculate time-averaged turbulent flow field around a standard tall building proposed by the common advisory aeronautical research council （CAARC）. The computed Reynolds Stress results were then used to modify the power spectral destiny functions of wind velocity at those near building positions. The fluctuating wind velocity field around the CAARC building was numerically generated by the developed hybrid simulation method. The physical properties of the simulated wind velocity filed were calibrated by comparing the power spectral destiny functions, cross correlation functions and spatial corre- lation factors with their respective target values. The results of the CAARC building demonstrate the accuracy and efficiency of the synthesized numerical approach in simulating the turbulent wind fields disturbed by the given building.