二次元円柱後流のスパン方向に同時に存在する異なった渦放出周波数間の非線形干渉(流体工学,流体機械)

概要

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It is known that the low frequency fluctuation of about 1/20 of the Strouhal frequency exists in the wake behind a two-dimensional circular cylinder. Also, it is known that different vortex shedding frequencies exist at the same time in the span-wise direction of the wake, and these frequencies are classified into low-mode and high-mode frequencies with separation of approximately 1/20 of the Strouhal frequency by taking the Strouhal frequency as threshold. Since the difference of these two frequencies and the low frequency fluctuation are nearly the same, the different vortex shedding frequencies are considered to be the cause of the low frequency fluctuation. Moreover, this coincidence of the frequencies is suggesting presence of nonlinear interaction between two frequencies which would be contributing to the energy cascade of turbulence. In this study, from velocity measurements, a particular phase difference TSC (Trans-Spectral Coherence) analysis was conducted to investigate the presence of nonlinear interaction in the wake behind the two-dimensional circular cylinder.
一般社団法人日本機械学会の論文
2004-11-25