粘弹性管流中的无惯性湍流
Inertialess turbulence in viscoelastic pipe flow
- Institute of Science and Technology Austria (ISTA)（奥地利科学技术研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究在粘弹性管流中实验发现，即使在雷诺数远低于理论预测最低值四个数量级时，高浓度聚合物溶液仍能触发纯弹性湍流，证实无惯性湍流的存在。
AI中文摘要：
湍流通常与惯性主导的流体运动同义，涉及高速度和大空间尺度。相反，在复杂流体中，弹性材料特性即使在任意小的惯性下也能促进并维持类似湍流的运动。然而，达到这种纯弹性湍流状态的常见途径严格上仅发生在具有弯曲流线的特定流动中，从而排除了管流等典型情况。通过在管道实验中跨越前所未有的弹性和粘度范围研究稀聚合物溶液，我们追踪到一种先前被认为需要有限惯性的不稳定性，其雷诺数比理论预测的最低水平低四个数量级。在足够高的聚合物浓度和大剪切速率下，转变阈值的突然下降证实已达到消失惯性极限，因此观察到的波动运动纯属弹性起源。
英文摘要：
Turbulence is synonymous with inertia dominated fluid motion, entailing high velocities and large spatial scales. Conversely, in complex fluids, elastic material properties can promote and sustain turbulent-like motions even at arbitrarily small inertia. The common route to this purely elastic state of turbulence, however, strictly occurs only in specific flows with curved streamlines, thus excluding canonical cases such as pipe flow. Investigating dilute polymer solutions in pipe experiments across an unprecedented elasticity and viscosity range, we trace an instability, previously assumed to require finite inertia, to Reynolds numbers four orders of magnitude below the theoretically predicted minimum level. At sufficiently high polymer concentrations and large shear rates, an abrupt drop in the transition threshold confirms that the vanishing inertia limit has been reached, and consequently that the fluctuating motions observed are of purely elastic origin.
