正弦型来流条件下大气表面层特性的研究

导出了正弦来流条件下的大气表面层平均风速及湍流强度的计算式。在环境风洞中使用粒子图像速度仪（PIV）对正弦来流条件下的大气表面层平均风速廓线和湍流强度进行了测量。结果表明：正弦型来流条件下所模拟的大气表面层在不同高度上风速均呈正弦规律波动，测量得到平均风速与导出计算式结果一致，相当于在定常风速廓线基础上叠加一个周期与主流风速一致、振幅随高度变化的正弦波动函数。每一个相位的湍流强度沿高度的分布均与定常来流条件下的湍流强度有着相似的变化规律，且湍流强度的大小随相位变化呈现一定的波动性。

Characters of sinusoidal atmospheric surface layer

The computing formulas of the phase average velocity profile and turbulence intensity in sinusoidal atmospheric surface layer （ASL） were derived. And sinusoidal unsteady ASL was measured by particle image velocimetry （PIV） in the environmental wind tunnel. The PIV captured data were processed basing on a short time phase average method. The results show that the average velocity is consistent with the one from the computing formula. Moreover, the unsteady average velocities of the ASL along the height uniformly present sinusoidal, with each of them equivalent to adding to steady velocity profile on the corresponding height a sinusoidal func- tion whose period is the same as main stream while the swing is determined by that height. At each phase, the distribution of the turbulence intensity along the length coincides with that of the steady inflow, and the turbulence intensity presents certain fluctuations with phase variety.