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应用哈特曼波前传感器测量了准直平行光通过低速热射流流场后的畸变波前时间序列,对该波前时间序列进行了本征正交分解(POD)和低阶近似研究,对比研究了16#,1008#数据点处的低阶近似波前时间序列和测量波前时间序列。结果表明,畸变波前可用本征正交分解基来展开,应用少量的低阶本征正交分解基即可捕捉到波前的主要信息,并且随着重构模式数的增加,低阶近似波前更加逼近测量波前。由于波面上不同位置处相位脉动量的空间相关性各异,因此选用相同的重构模式数时不同数据点处的重构精度也不一样。
The Hartmann wavefront sensor was used to measure the time series of the distorted wavefront of collimated parallel light passing through the low velocity thermal jet. The wavefront time series were studied by using the POD and the low order approximation. The lower order approximate wavefront time series and the measured wavefront time series at 16 #, 1008 # data points are studied. The results show that the distortion wavefront can be expanded by using the intrinsic orthogonal decomposition base. The main information of the wavefront can be captured by using a small number of low-order eigen-orthogonal decomposition bases. With the increase of the number of reconstruction modes, The wavefront is closer to the measurement wavefront. Because of the different spatial correlations of phase ripple at different locations on the wavefront, the reconstruction accuracy at different data points is different when selecting the same reconstruction mode number.