复杂山地环境下脉动风速谱研究

进行了8种坡度下单个三维山体的模型风洞试验,讨论了山体各位置脉动风速谱的变化规律,以及坡度对脉动风速谱的影响.结果表明:背风面山脚0.8h高度以下位置,脉动风速功率谱与来流风速谱相比,功率谱峰值明显增大,峰值频率向高频移动,单峰特征明显,频带变窄.除此以外的背风面其他位置、迎风面以及山顶位置的脉动风速功率谱与来流风速谱基本一致.提出了山体背风面脉动风速能量由来流湍流能量和山体尾流涡旋能量构成的思想,将来流脉动风速谱与涡旋谱进行分离,并根据试验数据拟合,提出了保守的涡旋谱的计算公式.根据不同坡度山体的试验,得出了0.5为涡旋产生与否的临界坡度.

Research on the Wind Speed Spectrum of Complex Mountainous Environment

Wind tunnel tests of single 3D hilly terrain for eight slopes were carried out, and the wind speed spectrum in different places and the effect of the hill slope were studied. The results show that the effect of the hill at the windward and hilltop far away from the hill can be ignored; at the leeward under the height of 0.8 h, the peak value of the wind speed spectrum increases and peak frequency moves to a high frequency. There is a single peak and the frequency bandwidth becomes narrower. It is assumed that the fluctuant wind speed energy at the leeward is composed of the inflow turbulence energy and the vortex energy induced by the hill, so the vortex energy can be separated. The calculation model of the vortex spectrum was proposed by the fitting of the wind tunnel test data. The wind tunnel test of different hill slopes shows that the slope 0.5 is the critical slope where the vortex will appear.