대한기계학회:학술대회논문집 (Proceedings of the KSME Conference)
- 대한기계학회 2000년도 춘계학술대회논문집B
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- Pages.661-666
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- 2000
Cinematic PIV에 의한 실린더 후류의 위상평균된 3차원 구조
Phase-Locked Three-Dimensional Structures in the Cylinder Wake Observed from Cinematic PIV Data
- 발행 : 2000.04.20
초록
Near-wake flow field of a circular cylinder is studied by means of a cinematic PIV system with high sampling rate and large internal memory block. Experiments are conducted in a closed-cycle water tunnel system and a cross-correlation algorithm in conjunction with FFT (Fast Fourier Transform) analysis and an offset correlation technique is used for vector processing. With the help of very high sampling frequency compared to the shedding frequency, it is possible to obtain phase-averaged information of the three-dimensional wake, even though the shedding is not forced but natural. Phase-locked vortical structures observed simultaneously from the spanwise and cross-stream planes are displayed in the wake-transition regime where fine-scale secondary vortices have a spanwise wavelength or around one diameter. Spatial relations and temporal evolutions of the primary Karman vortex and the secondary vortex are also discussed schematically.
키워드