Empirical mode decomposition and Hilbert transforms for analysis of oil-film interferograms
Empirical mode decomposition and Hilbert transforms for analysis of oil-film interferograms
复制标题
用于油膜干涉图分析的经验模态分解和希尔伯特变换
DOI：
10.1088/0957-0233/21/10/105405
复制
发表时间：
2010
影响因子：
2.4
通讯作者：
I. Marusic
中科院分区：
文献类型：
--
作者：
K. Chauhan;H. Ng;I. Marusic
油膜干涉测量法正迅速成为壁面湍流研究中直接测量壁面剪切应力的首选方法。尽管它被广泛认为是最准确的技术，但它确实具有固有的测量不确定性，其中之一与确定条纹间距有关。这是本文的重点。传统的分析方法涉及一定程度的用户输入，因此具有一定的主观性。在本文中，我们将经验模态分解（EMD）和希尔伯特变换视为分析油膜干涉图的替代工具。与常用的基于傅立叶的技术相比，这种新方法主观性较小，并且由于它基于希尔伯特变换，因此对于处理幅度和频率调制数据具有优越性。这使得它对于干涉图质量的巨大差异特别稳健。
Oil-film interferometry is rapidly becoming the preferred method for direct measurement of wall shear stress in studies of wall-bounded turbulent flows. Although being widely accepted as the most accurate technique, it does have inherent measurement uncertainties, one of which is associated with determining the fringe spacing. This is the focus of this paper. Conventional analysis methods involve a certain level of user input and thus some subjectivity. In this paper, we consider empirical mode decomposition (EMD) and the Hilbert transform as an alternative tool for analyzing oil-film interferograms. In contrast to the commonly used Fourier-based techniques, this new method is less subjective and, as it is based on the Hilbert transform, is superior for treating amplitude and frequency modulated data. This makes it particularly robust to wide differences in the quality of interferograms.