Dynamics and fragmentation of small inextensible fibres in turbulence
Dynamics and fragmentation of small inextensible fibres in turbulence
复制标题
湍流中不可延伸的小纤维的动力学和破碎
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
J. Bec
中科院分区：
文献类型：
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作者：
Sofía Allende;C. Henry;J. Bec
在一个完全发展的、均匀的、各向同性的湍流中，研究了小的、脆的、柔性的、不可扩展的纤维的破碎。这样的小纤维大部分时间都是完全拉伸的，它们的动态跟随硬杆。然后它们可以突破拉伸破坏，即当张力高于给定阈值时。纤维受到强烈挤压时会弯曲。在这些罕见的间歇性屈曲事件中，它们可能在弯曲破坏下断裂，即当曲率超过阈值时。对流体流动和纤维动力学进行了精细尺度的大规模模拟，以提供这两种破碎过程的统计数据。这为建立精确的宏观模型提供了基础，即破碎率和粒径分布，可用于预测纤维粒径分布的时间演变。为湍流破碎化和由此产生的种群动态的一般性质提供了证据。结果表明，破裂的统计完全由拉格朗日流体速度梯度的概率分布决定。这种方法指出，唯一相关的无量纲参数是平衡流动拉伸到纤维弹性力的局部柔韧性。本文是“流体动力学、软物质和复杂系统：最新结果和新方法”主题的一部分。
The fragmentation of small, brittle, flexible, inextensible fibres is investigated in a fully developed, homogeneous, isotropic turbulent flow. Such small fibres spend most of their time fully stretched and their dynamics follows that of stiff rods. They can then break through tensile failure, i.e. when the tension is higher than a given threshold. Fibres bend when experiencing a strong compression. During these rare and intermittent buckling events, they can break under flexural failure, i.e. when the curvature exceeds a threshold. Fine-scale massive simulations of both the fluid flow and the fibre dynamics are performed to provide statistics on these two fragmentation processes. This gives ingredients for the development of accurate macroscopic models, namely the fragmentation rate and daughter-size distributions, which can be used to predict the time evolution of the fibre size distribution. Evidence is provided for the generic nature of turbulent fragmentation and of the resulting population dynamics. It is indeed shown that the statistics of break-up is fully determined by the probability distribution of Lagrangian fluid velocity gradients. This approach singles out that the only relevant dimensionless parameter is a local flexibility which balances flow stretching to the fibre elastic forces. This article is part of the theme issue ‘Fluid dynamics, soft matter and complex systems: recent results and new methods’.
影响因子：
3.3
作者：
Buaria, Dhawal;Pumir, Alain;Yeung, P. K.
通讯作者：
Yeung, P. K.