We revisit the issue of Lagrangian irreversibility in the context of recent results [Xu, {et al.}, PNAS, 111, 7558 (2014)] on flight-crash events in turbulent flows and show how extreme events in the Eulerian dissipation statistics are related to the statistics of power-fluctuations for tracer-trajectories. Surprisingly, we find that particle trajectories in intense dissipation zones are dominated by energy gains sharper than energy losses, contrary to flight-crashes, through a pressure-gradient driven take-off phenomenon. Our conclusions are rationalised by analysing data from simulations of three-dimensional intermittent turbulence, as well as from non-intermittent decimated flows. Lagrangian irreversibility is found to persist even in the latter case, wherein fluctuations of the dissipation rate are shown to be relatively mild and to follow probability distribution functions with exponential tails.

中文翻译：

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完全发展的湍流中的拉格朗日不可逆性和欧拉耗散

我们在湍流中的飞行事故事件的最新结果[Xu，{et al。}，PNAS，111，7558（2014）]的背景下重新审视了拉格朗日不可逆性的问题，并显示了欧拉耗散统计中的极端事件是如何发生的与追踪器轨迹的功率波动统计有关。出乎意料的是，我们发现，在强耗散区中，通过压力梯度驱动的起飞现象，与飞行崩溃相反，能量轨迹比能量损耗更陡峭，而能量轨迹占主导地位。通过分析来自三维间歇湍流模拟以及非间歇抽取流动的数据，我们的结论是合理的。即使在后一种情况下，拉格朗日不可逆性仍然存在，