中文摘要：

采用数值模拟方法研究了静叶尾迹的非定常流动特性,通过改变动叶与静叶之间的轴向间距和动叶的转速,结合不同工况下的等熵图,利用傅里叶变换（FFT）对动叶升力系数和阻力系数进行了频谱变换,并分析了其频谱特性与动静叶间轴向间距和动叶转速之间的关系.结果表明：随着轴向间距的增大,尾迹涡脱落频率变化不大,但功率谱密度变化较大,引起下游叶栅通道熵值增大,导致下游动叶周围能量损失增加;转速的增大使尾迹涡脱落频率增加,功率谱密度变大,同时下游叶栅通道熵值也逐渐增大,表明尾迹涡带来动叶周围更大的能量损失.

英文摘要：

The unsteady flow characteristics of vane wake was numerically simulated.Combined with instantaneous entropy obtained under different working conditions,spectral transformation of blade lift coefficient and drag coefficient was carried out by changing the axial spacing of stator-rotor and the speed of rotor using fast Fourier transform（FFT）,after which relationgships of spectrum characteristics varying with the axial spacing and the speed were analyzed.Results show that with the rise of axial spacing,the vortex shedding frequency of wake basically remains stable,but the power spectral density varies a lot,resulting in increased entropy in downstream channel of cascade and raised energy loss around downstream blade;whereas with the rise of rotor speed,both the vortex shedding frequency and the power spectral density increase,and the entropy in downstream channel of cascade rises also,indicating that higher energy loss is produced around blade by wake vortex.