Double helix vortex breakdown in a turbulent swirling annular jet flow

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2018-03-28

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Vanierschot, M.
Perçin, Mustafa
van Oudheusden, B. W.

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In this paper, we report on the structure and dynamics of double helix vortex breakdown in a turbulent annular swirling jet. Double helix breakdownhas been reported previously for the laminar flow regime, but this structure has rarely been observed in turbulent flow. The flow field is investigated experimentally by means of time-resolved tomographic particle image velocimetry. Notwithstanding the axisymmetric nature of the time-averaged flow, analysis of the instantaneous three-dimensional (3D) vortical structures shows the existence of a vortex core along the central axis which breaks up into a double helix downstream. The winding sense of this double helix is opposite to the swirl direction (m = -2) and it is wrapped around a central vortex breakdown bubble. This structure is quite different from double helix breakdown found in laminar flows where the helix is formed in the wake of the bubble and not upstream. The double helix precesses around the central axis of the jet with a precessing frequency corresponding to a Strouhal number of 0.27.

Subject Keywords

Mode, Simulation, Sensitivity, Recirculation, Dynamics, Pipe, Simulation;stabilized combustor, Sensitivity, Recirculation, Dynamics, Pipe, Stabilized combustor

URI

https://hdl.handle.net/11511/42681

Journal

PHYSICAL REVIEW FLUIDS

DOI

https://doi.org/10.1103/physrevfluids.3.034703

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Department of Aerospace Engineering, Article

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Citation Formats

M. Vanierschot, M. Perçin, and B. W. van Oudheusden, “Double helix vortex breakdown in a turbulent swirling annular jet flow,” PHYSICAL REVIEW FLUIDS, pp. 0–0, 2018, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/42681.