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不连续的过渡到活跃的阴性流.

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  • 1Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.

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在活性流体中,过渡到活性流是不连续的,在层状和混乱的流量状态之间,速度和双稳定性突然跳跃. 这与在封闭系统中观察到的连续过渡形成鲜明对比.

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科学领域:

  • 物理 物理学 物理
  • 流体动力学 流体动力学
  • 软物质物理学 软物质物理学

背景情况:

  • 活性流体在低雷诺兹数时表现出混乱的流动,称为活性流.
  • 活跃流的统计性质已被理解,但从层状流向流的过渡仍然不清楚.

研究的目的:

  • 在无边界,无缺陷的活体体质中,研究从层状流向流的过渡.
  • 描述这种过渡的性质,无论是连续的还是不连续的.

主要方法:

  • 一个最小模型的模拟,用于活跃的敌人.
  • 分析平均平方速度,双稳定性,歇斯底里和有限时间的利亚普诺夫指数.

主要成果:

  • 过渡到活跃的流是不连续的,标志着平均平方速度的跳跃.
  • 观察了层状流和混沌流之间的双位性和歇斯底里.
  • 为过渡确定了一个关键活动号码 (A* ≈ 4900).
  • 在过渡的下方发生导致振荡和长时间混沌过渡的亚临界分叉.

结论:

  • 在无边界的活体体质中,过渡到活跃流是不连续的.
  • 斯托克斯流中的远程水力动力相互作用可能会抑制流状态的空间共存,导致不连续的过渡.
  • 这些发现与封闭系统中的连续过渡形成鲜明对比.