三方柱表面风压脉动的时域特性

以三方柱模型实验结果为依据，讨论了建筑物表面风压脉动的极值分布情况。给出了压力脉动系数的定义，分别研究了排列方式、间距比、高度、尖角等不同因素对脉动压力系数的影响，指出时均压力系数绝对值较大的位置出现较大脉动压力系数的概率就低，并发现在间距比2．5－3．0间流场可能存在突变。详细分析了瞬间极值的时间特性，指出瞬间极值来得快，去得也快，只在极短的时间内作用于建筑物的表面，十分钟时距内大部分时间的瞬时压力都比瞬时极值小得多。

Surface Pressure Fluctuation of Three Square Cylinders in Time Domain

In this paper, based on the experiments of flow over three square cylinders, the peak values of the fluctuating pressure on the surface were discussed. A pressure fluctuation coefficient (PFC) was difined. The influence on the PFC of configuration, space ratio, height and sharp corner was studied respectively. It is indicated that the high absolute time-average pressure coefficient causes low fluctuation of PFC. And a sudden change of flow field maybe occur between the space ratios of 2. 5~3. 0. The character of instant peak value in time domain is also analyzed for details. The results show that the instant peak pressure value arises sharply and briefly, exerting pressures on the surfaces of building only for a short time.