Lagrangian analysis of the fluid transport induced by the interaction of two co-axial co-rotating vortex rings

Lin, Haiyan; Xiang, Yang; Qin, Suyang; Xu, Hanlin; Liu, Hong

doi:10.1007/s42241-020-0074-5

Cited by 3 publications

(1 citation statement)

References 37 publications

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“…As the Lagrangian skeleton of flow, Lagrangian coherent structures (LCSs) provide a geometrical view of flow structures and characterize fluid transport and deformation over a certain period. [21,22] Although there are some inconsistencies, the ridges of the FTLE are heuristic indicators of hyperbolic Lagrangian coherent structures. [19,23,24] This paper applies the FTLE ridges to analyze the fluid transport.…”

Section: Finite-time Lyapunov Exponent Fieldmentioning

confidence: 99%

Effect of pressure evolution on the formation enhancement in dual interacting vortex rings

Dong¹,

Xiang²,

Liu³

et al. 2022

Chinese Phys. B

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In the biological locomotion, the ambit pressure is of particular importance to use as a means of propulsion. The multiple vortex rings have been proved to generate additional thrust by interaction, but the mechanism of this thrust enhancement is still unknown. This study examines the effect of ambit pressure on formation enhancement in interacting dual vortex rings. The vortex rings, which have the same formation time, are successively generated in a piston-cylinder apparatus. The finite-time Lyapunov exponent (FTLE) visualizes the flow fields as an indication of Lagrangian coherent structures (LCSs), and the pressure field is calculated based on digital particle image velocity (DPIV). We extract the back pressure of the rear vortex in dual vortices and the back pressure circulation $\varGamma_b$, which is defined as a form of overpressure circulation $\varGamma_p$. The $\varGamma_b$ has a positive linear relationship with $\varGamma_p$. A critical interval distance $d_{cr}^*$ in a range of 0.32$\sim$0.42 is found where $\varGamma_b$ and $\varGamma_p$ reach maximum synchronously, which leads to a “full-interaction mode”. Moreover, an “over-interaction mode” and an “under-interaction mode” are proposed when the dimensionless interval distance $d^*$ is smaller or larger than $d_{cr}^*$. To conclude, the high back pressure caused by vortex interaction can enhance the formation of vortex rings and lead to high thrust.

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Section: Finite-time Lyapunov Exponent Fieldmentioning

confidence: 99%

Effect of pressure evolution on the formation enhancement in dual interacting vortex rings

Dong¹,

Xiang²,

Liu³

et al. 2022

Chinese Phys. B

Self Cite

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How sensitive are Lagrangian coherent structures to uncertainties in data?

BADZA

Mattner²,

Balasuriya³

2023

Physica D: Nonlinear Phenomena

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Vortex structures evolution in supersonic mixing layers with different inlet Reynolds numbers based on the Lagrangian method

Xing

Zhang

et al. 2021

AIP Advances

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The supersonic mixing layer is a typical flow structure in an aircraft’s optical seeker. The free incoming flow and cooling jet form a mixing layer through shearing. In most cases, the flow has become a fully developed turbulent due to complex factors during flight. This paper mainly focuses on the influence of the inlet Reynolds number on the development of the supersonic mixing layer. The rescaling/recycle method is used to generate turbulence at the inlet of the mixing layer. The results show that when the turbulence of the high-speed flow is strong, the transition position of the mixing layer will be advanced and the mixedness will be enhanced. The mixing efficiency is high at the position corresponding to the vortex in the mixing layer. Finally, the Lagrangian coherent structure and particle tracking methods are used to analyze different mixing processes, and the entrainment characteristics of the vortex are studied.

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Lagrangian analysis of the fluid transport induced by the interaction of two co-axial co-rotating vortex rings

Cited by 3 publications

References 37 publications

Effect of pressure evolution on the formation enhancement in dual interacting vortex rings

Effect of pressure evolution on the formation enhancement in dual interacting vortex rings

How sensitive are Lagrangian coherent structures to uncertainties in data?

Vortex structures evolution in supersonic mixing layers with different inlet Reynolds numbers based on the Lagrangian method

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