论文标题
抗粘弹性流动的直流通道中弹性湍流的通用相干结构
Universal coherent structures of elastic turbulence in straight channel with viscoelastic fluid flow
论文作者
论文摘要
在本研究中，我们研究了直2D通道粘弹性流体流动中弹性湍流的流动结构和特性，并测试了早期观察结果。我们发现了共存条纹和河流涡旋的弱不稳定相干结构（CS）的自组织循环过程，前者被开尔文·赫尔莫尔兹（Kelvin-Helmholtz）类似的不稳定摧毁，导致了混乱的结构。该序列会定期重复自己，导致随机稳态。这种自我维持的过程（SSP）非常类似于理论上和实验性地研究直流通道流中的牛顿湍流。出乎意料的新成分是观察弹性波，由于弹性湍流能谱中的锋利幂律衰减之前的能量从较小的尺度泵送到较小的尺度，这对于CSS和SSP生成至关重要。报道的发现表明，通过弹性和牛顿流体的线性稳定平面剪切流在线性稳定的平面剪切流中，CSS在过渡到湍流中的普遍性。
In the present study, we investigated flow structures and properties of elastic turbulence in straight 2D channel viscoelastic fluid flow and tested earlier observations. We discovered self-organized cycling process of weakly unstable coherent structures (CSs) of co-existing streaks and stream-wise vortices, with the former being destroyed by Kelvin-Helmholtz-like instability resulting in chaotic structures. The sequence periodically repeats itself leading to stochastically steady state. This self-sustained process (SSP) remarkably resembles one investigated theoretically and experimentally for Newtonian turbulence in straight channel flow. The unexpected new ingredient is the observation of elastic waves, which finds to be critical for existence of CSs and SSP generation due to energy pumping from large to smaller scales preceding sharp power-law decay in elastic turbulence energy spectrum. The reported finding suggests the universality of CSs in transition to turbulence via self-organized cycling (SSP) in linearly stable plane shear flows of both elastic and Newtonian fluids.
