Regeneration cycle and the covariant Lyapunov vectors in a minimal wall turbulence
Regeneration cycle and the covariant Lyapunov vectors in a minimal wall turbulence
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最小壁湍流中的再生循环和协变李雅普诺夫向量
DOI：
10.1103/physreve.92.023022
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发表时间：
2015
影响因子：
2.4
通讯作者：
and Michio Yamada
中科院分区：
文献类型：
--
作者：
Masanobu Inubushi;Shin-ichi Takehiro;and Michio Yamada
将壁面湍流视为一个混沌动力系统，从轨道不稳定性的角度出发，利用李雅普诺夫协变分析方法研究了最小壁面湍流中的再生周期。Ginelli phy。[j].科学通报，1999,13(6):557 - 557。我们将再生周期分为两个阶段，并用局域Lyapunov指数和Navier-Stokes湍流的协变Lyapunov向量来表征它们。特别地，我们在数值上表明，阶段(i)由与蜿蜒模式和流向涡度相关的不稳定性主导，而阶段（ii）没有不稳定性。此外，我们讨论了再生循环的机制，利用能量预算分析。
Considering a wall turbulence as a chaotic dynamical system, we study regeneration cycles in a minimal wall turbulence from the viewpoint of orbital instability by employing the covariant Lyapunov analysis developed by [F. Ginelli Phys. Rev. Lett. 99, 130601 (2007)PRLTAOPRLTAO0031-900710.1103/PhysRevLett.99.130601]. We divide the regeneration cycle into two phases and characterize them with the local Lyapunov exponents and the covariant Lyapunov vectors of the Navier-Stokes turbulence. In particular, we show numerically that phase (i) is dominated by instabilities related to the sinuous mode and the streamwise vorticity, and there is no instability in phase (ii). Furthermore, we discuss a mechanism of the regeneration cycle, making use of an energy budget analysis.