Scalar dissipation rate measurements in a starting jet
Scalar dissipation rate measurements in a starting jet
复制标题
起始射流中的标量耗散率测量
DOI：
10.1007/s00348-014-1685-9
复制
发表时间：
2014
影响因子：
2.4
通讯作者：
A. Taylor
中科院分区：
文献类型：
--
作者：
N. Soulopoulos;Y. Hardalupas;A. Taylor
标量耗散率的测量是在脉冲启动的气体射流中使用平面激光诱导荧光进行的。 The measurements are well-resolved spatially.实验噪声对本实验的恶化影响采用维纳滤波器进行处理，该滤波器被证明适用于这种大规模非均匀流。根据滤波误差的显式计算确定，标量耗散率的精度在 20% 以内。详细分析了滤波后保留的残余场，它们的统计特性表明它们与白噪声非常相似。标量场的修正水平很小，但标量耗散率的修正水平约为 40%。使用建模光谱和测量的空间分辨率对滤波操作进行的检查表明，对于高达 1,000 的泰勒尺度雷诺数，维纳滤波器在标量耗散率估计中会产生约 30% 的误差。我们针对常见的实验情况讨论了该模型的含义，并指出了与信噪比的改进相比，提高空间分辨率的相对优点。
Measurements of the scalar dissipation rate are taken in an impulsively started gas jet, using planar laser-induced fluorescence. The measurements are well-resolved spatially. The deteriorating effect of experimental noise on this experiment is treated with a Wiener filter, which is shown to be applicable to this large-scale inhomogeneous flow. The accuracy of the scalar dissipation rate is within 20 %, as determined from an explicit calculation of the filtering errors. The residual fields that remain after the filtering are analysed in detail, and their statistical properties show that these resemble white noise to a good approximation. The level of corrections is minimal for the scalar field but it is of the order of 40 % for the scalar dissipation rate. An examination of the filtering operation using modelled spectra and the measured spatial resolution shows that the Wiener filter produces errors in the estimate of the scalar dissipation rate ∼30 %, for Taylor-scale Reynolds number up to 1,000. The implications of this modelling are discussed with respect to common experimental situations and point out the relative merits of improving the spatial resolution as compared to improvements in the signal-to-noise ratio.