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arXiv · 2402.01996

A self-induced mechanism of large-scale helical structures in compressible turbulent flows

Zheng Yan·Jianchun Wang·Lifeng Wang·Zhu Lei·Junfeng Wu·Junyi Duan·Fulin Tong·Xinliang Li·Changping Yu
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Abstract

A novel self-sustaining mechanism is proposed for large-scale helical structures in compressible turbulent flows. The existence of two channels of subgrid-scale and viscosity terms for large-scale helicity evolution is confirmed for the first time, through selecting a physical definition of the large-scale helicity in compressible turbulence. Under the influence of the fluid element expansion, it is found that the helicity is generated at small scales via the second-channel viscosity, and the inverse cross-scale helicity transfers at inertial scales through the second-channel helicity flux. Together, they form a self-induced mechanism, which provides a physical insight into the long-period characteristic of large-scale helical structures in the evolution of compressible flow systems.

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Zheng Yan, Jianchun Wang, Lifeng Wang, Zhu Lei, Junfeng Wu, Junyi Duan, Fulin Tong, Xinliang Li, Changping Yu. 2024-02-03. A self-induced mechanism of large-scale helical structures in compressible turbulent flows. https://doi.org/10.1103/physrevfluids.9.094603

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