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Turbulent Energy Cascade and Mixing Induced by the Axis-Offset Collision of Two Vortex Rings

Nguyen Institute of Engineering and Technology, Thu Dau Mot University, Binh Duong Province, Viet Nam|
V.L. (55826212100) |

Fluid Dynamics Số 6, năm 2022 (Tập 57, trang 845-864)

ISSN: 154628

ISSN: 154628

DOI: 10.1134/S0015462822100391

Tài liệu thuộc danh mục:



Từ khóa: Computational complexity; Large eddy simulation; Mixing; Spectroscopy; Axis-offset collision; Circulation ratio; Collision region; Energy cascade; Energy spectrum; Reconnection; Small-scale vortices; Turbulent energies; Turbulent energy cascade; Vortex rings; Vortex flow
Tóm tắt tiếng anh
Abstract: The axis-offset collision of two vortex rings with their various circulation ratios was numerically investigated using the vortex-in-cell method combined with the large-eddy simulation model. For the ratio of 0.1, the robust ring, moving through the weak ring, remains unchanged in its shape and deforms the weak ring. The small-scale vortices are not generated at this ratio. For the ratio of 0.2, the robust ring is still maintained after collision, while parts of the weak ring near the collision regions are entrained by the robust ring. The interaction of these entrained parts with the robust ring produces many small-scale vortices. For the ratio of 0.5, the robust ring is broken into smaller-scale vortices, and the interaction of these vortices with the entrained parts of the weak ring results in many other small-scale vortices. The reconnection takes place at the unity ratio, at which half the first ring links another half the second one to form elliptical vortex rings and produce various vortices including small rings in the collision regions. These rings are rapidly distorted and interact with small vortices surrounding them to establish clusters of various-scale vortices. The energy spectrum of induced flow at high wavenumbers approaches the k−5/3 slope of Kolmogorov’s theorem after the collision, and mixing two vortex rings is the best at the ratio of 0.5. It is stated that the vortex reconnection and formation, as well as the turbulent energy cascade and mixing efficiency, significantly depend on the initial circulation ratio of two vortex rings. © 2022, Pleiades Publishing, Ltd.

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