Title: Intermittent fluctuations determine the nature of chaos in turbulence Show Chinese title

Title: 间歇性波动决定了湍流中混沌的性质。

Abstract: We adapt recent ideas for many-body chaos in nonlinear, Hamiltonian fluids [Murugan \textit{et al.}, Phys. Rev. Lett. 127, 124501 (2021)] to revisit the question of the Reynolds number Re dependence of the Lyapunov exponent $\lambda\propto{\rm Re}^\alpha$ in fully developed turbulence. The use of such decorrelators allow us to investigate the interplay of the competing effects of viscous dissipation and nonlinearity. We obtain a precise value of $\alpha = 0.59 \pm 0.04$ and show that departure from the Kolmogorov mean field result $\lambda \propto \sqrt{{\rm Re}}$ is a consequence of the intermittent fluctuations in the velocity-gradient tensor. The robustness of our results are further confirmed in a local, dynamical systems model for turbulence. Show Chinese abstract

Abstract: 我们借鉴了最近关于非线性哈密顿流体中多体混沌的思想[Murugan \textit{等}, Phys. Rev. Lett. 127, 124501 (2021)]，重新审视了雷诺数Re对完全发展湍流中李亚普诺夫指数$\lambda\propto{\rm Re}^\alpha$依赖性的问题。使用这类去相关器使我们能够研究粘性耗散和非线性的竞争效应之间的相互作用。我们得到了精确的$\alpha = 0.59 \pm 0.04$值，并表明偏离科莫戈洛夫平均场结果$\lambda \propto \sqrt{{\rm Re}}$是速度梯度张量间歇性波动的结果。我们在一个局部的动力系统模型中进一步确认了我们结果的稳健性。