网格湍流CAARC模型风洞实验

An experiment on a CAARC model in grid turbulent flow

对大气湍流边界层的真实模拟是风工程风洞模拟实验所要满足的基本条件之一。平均速度剖面 ,湍流度剖面 ,积分尺度和风谱是反映大气湍流边界层流动的四个最基本的因素。本文首先研究了不同孔隙率的均匀网格湍流场的流动特性 ,得到湍流度、积分尺度以及风谱的变化规律 ,然后在变化其中某一个因素而保持另外三个因素不变的条件下 ,研究了处于均匀网格湍流场中的CAARC模型风荷载响应的变化 ,从而确定每一个因素的独立变化对模型所受风荷载的影响。实验结果表明湍流度和积分尺度对结构物所受风荷载都有很重要的影响 ,在风洞大气湍流边界层模拟中应该予以充分的考虑 ,否则将会引起风荷载实验结果的偏差。

Simulation of the atmospheric turbulent boundary layer is a prerequisite in wind tunnel simulation experiments. Mean velocity profile, turbulence intensity profile, integral scale and wind spectra are the most fundamental characteristics that describe the atmospheric turbulent boundary layer flow. These four characteristics of homogeneous grid turbulence flow of different grid porosities are studied at first. Then by varying one of the four characteristics while holding the other three ones constant, the changes of the effects on a CAARC model that is fixed in such a flow are investigated. Thus, the independent influences of these four characteristics on structures are obtained. The experimental results show that both turbulence intensity and integral scale have significant influences on the wind load of structures.