不同风场下开、闭鞍型屋盖脉动风压特性分析

在B类和D类风场条件下,对底部开敞和封闭的鞍型索网屋盖刚性模型进行了风洞测压试验.根据同步测量的风压数据,分析了不同风场条件下这两类鞍型索网屋盖上的脉动风压的分布规律及相互关系;通过对开敞和封闭的鞍型屋盖表面脉动风压功率谱及风压时程的对比分析,考察底部开敞对鞍型屋盖脉动风压分布特性的影响规律.风场对脉动风压系数分布有较大影响;脉动风压的分布类似于平均风压场的分布规律;底部封闭鞍型索网屋盖的脉动风压能量主要集中在折减频率小于0.3范围内,而底部开敞鞍型屋盖脉动风压的高频段能量高于底部封闭情况.

Fluctuating Wind Pressure Characteristics on Saddle Roof with and Without Enclosed Wall Under Different Terrain Conditions

The wind tunnel tests on rigid models of saddle-shape cable roofs with and without enclosed wall were carried out in exposure categories B and D. The distribution characteristics of the fluctuating wind pressures in the two wind fields and their relationships were investigated based on the wind pressure data obtained from the tests. Besides,the influences of the enclosed walls on fluctuating wind pressure distribution characteristics were also discussed in detail by comparing the power spectra and time series of wind pressures on the saddle roof model with and without the enclosed walls. The results indicate that the wind field category has significant effects on the fluctuating wind coefficients;the fluctuating wind distribution characteristics are similar to mean wind pressure distribution;the fluctuating wind pressure energy of saddle-shape cable roof with enclosed wall mainly distributes in the reduced frequency range lower than 0.3 Hz,but fluctuating wind pressure energy in high frequency range of saddle-shape cable roof without enclosed wall is higher than that of saddle-shape with enclosed wall.