Abstract
We present dynamic mode decomposition (DMD) for studying the hairpin vortices generated by hemisphere protuberance measured by two-dimensional (2D) time-resolved (TR) particle image velocimetry (PIV) in a water channel. The hairpins dynamic information is extracted by identifying their dominant frequencies and associated spatial structures. For this quasi-periodic data system, the resulting main Dynamic modes illustrate the different spatial structures associated with the wake vortex region and the near-wall region. By comparisons with proper orthogonal decomposition (POD), it can be concluded that the dynamic mode concentrates on a certain frequency component more effectively than the mode determined by POD. During the analysis, DMD has proven itself a robust and reliable algorithm to extract spatial-temporal coherent structures.
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Tang, Z., Jiang, N. Dynamic mode decomposition of hairpin vortices generated by a hemisphere protuberance. Sci. China Phys. Mech. Astron. 55, 118–124 (2012). https://doi.org/10.1007/s11433-011-4535-2
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DOI: https://doi.org/10.1007/s11433-011-4535-2