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Analysis of Flow Visualization Results Using Fourier Transform  

Koo, Bon-guk (Department of Naval Architecture and Marine Engineering, Changwon National University)
Park, Jun-mo (School of Electronic and Biomedical Engineering, Tongmyong University)
Kang, Yong-Duck (Department of Naval Architecture and Ocean Engineering, Dong-Eui University)
Publication Information
Journal of the Institute of Convergence Signal Processing / v.20, no.4, 2019 , pp. 199-204 More about this Journal
Abstract
In the boundary layer, vortical system has been analyzed by the statistical methods to identify the vortex interaction. However, there are the limitations in explaining vortices by the mean velocity or the standard deviation. This paper proposed a method to establish a frequency analysis by Fourier transform in order to simultaneously investigate various scale vortices. For this purpose, the flow visualization conducted to reveal a standing vortex, a hairpin vortex and a wake region around a hemisphere attached on a flat plate in a water channel. In addition, the velocity where the hairpin vortex was being generated in the wake region was measured by a hot-film anemometer. To observe changes in the vortex interaction, suction was applied through a hole in front of the hemisphere. For the evaluation of the proposed frequency analysis, the existing statistical results were compared to the frequency analysis that corresponds to the qualitative results of the flow visualization.
Keywords
Fourier Transform; Frequency; Standard Deviation; Hot-Film Anemometer; Hemisphere; Hairpin Vortex;
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Times Cited By KSCI : 2  (Citation Analysis)
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