はく離流れの非定常速度分布の位相平均解析(流体工学,流体機械)

概要

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The vortex structures in a separated flow region are generated by the motion of the separated shear layer caused by the introduction of periodic fluctuation. In order to investigate the principle motion of the velocity field, phase averaging was conducted to the velocity signals obtained by single hot-wire measurement. In phase averaging, Wavelet transformation was applied to obtained the dominant frequency and the characteristic phase angle in the fluctuation. It was found that the phase averaging technique by using Wavelet transformation is more useful in the process of averaging the data which include frequency modulation than the traditional phase averaging technique. The profiles of the phase-averaged velocity could be found and discussed. The profiles vary dynamically at each phase angle and show the periodic motion of the shear layer. The separated shear layer flutters with the external fluctuation in the mean flow. If the suitable frequency is selected in the external fluctuation, the separated flow region disappears in almost all phase angles owing to the depression of the shear layer near the wall.
社団法人日本機械学会の論文
2005-02-25