Hydrodynamic interactions and extreme particle clustering in turbulence
Hydrodynamic interactions and extreme particle clustering in turbulence
复制标题
湍流中的流体动力相互作用和极端粒子聚集
DOI：
10.1017/jfm.2021.1099
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发表时间：
2021
影响因子：
3.7
通讯作者：
H. Meng
中科院分区：
文献类型：
--
作者：
A. Bragg;Adam L. Hammond;R. Dhariwal;H. Meng
摘要扩展了哈蒙德和孟（J. Fluid Mech.，vol.921，2021，A16），我们给出了径向分布函数（r.d.f.）的惯性粒子在各向同性湍流中的不同Stokes数，$St$，表明r.d.f.随着间距r的减小，粒子数爆炸性地增长，随着碰撞半径的接近，呈现出r^{-6}$的比例关系，而与St$或粒子半径a$无关。为了理解这样的爆炸性聚类，我们纠正了Yavuz等人（Phys. Rev. Lett.，Vol.120，2018，244504）基于小的弱惯性粒子对之间的流体动力学相互作用。修正后的理论与实验结果的比较表明，Yavuz等人的理论低估了r.d.f.数量级的增长。为了解释这种差异，我们探索了几种理论中没有包括的这种差异的替代机制，并表明它们都不可能解释。这表明新的、尚未确定的物理机制正在发挥作用，需要进一步的研究和新的理论。
Abstract Expanding recent observations by Hammond & Meng (J. Fluid Mech., vol. 921, 2021, A16), we present a range of detailed experimental data of the radial distribution function (r.d.f.) of inertial particles in isotropic turbulence for different Stokes number, $St$, showing that the r.d.f. grows explosively with decreasing separation r, exhibiting $r^{-6}$ scaling as the collision radius is approached, regardless of $St$ or particle radius $a$. To understand such explosive clustering, we correct a number of errors in the theory by Yavuz et al. (Phys. Rev. Lett., vol. 120, 2018, 244504) based on hydrodynamic interactions between pairs of small, weakly inertial particles. A comparison between the corrected theory and the experiment shows that the theory by Yavuz et al. underpredicts the r.d.f. by orders of magnitude. To explain this discrepancy, we explore several alternative mechanisms for this discrepancy that were not included in the theory and show that none of them are likely the explanation. This suggests new, yet-to-be-identified physical mechanisms are at play, requiring further investigation and new theories.