arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新，休息一下吧，周末愉快~~
arXiv 2401.09710physics.flu-dyn
收藏

直Hele-Shaw池内弹性湍流共动类开尔文-亥姆霍兹剪切流中的压力测量

Pressure measurements in an elastically turbulent co-moving Kelvin-Helmholtz-like shear flow inside a straight Hele-Shaw cell

Jimreeves David M

备注：
This submission has been withdrawn by arXiv administrators as the second author was added without their knowledge or consent
发表信息：
Sādhanā 50, 242 (2025)
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

AI总结：

本研究通过直Hele-Shaw池中的共动剪切流实验，发现弹性湍流可在雷诺数低至0.1时激发，无需曲率或强扰动，推翻了传统认知。

摘要：

作为模拟细胞中生物流体流动和微小毛细血管中流动的实验模型，我们研究了稀聚合物溶液的共动剪切流。在压力驱动的Hele-Shaw池内，通过平行流以不同速度运动，形成了具有拐点的剪切流剖面。总体目标是探索导致弹性湍流（Elastic Turbulence）的可能不稳定性机制，该现象于二十年前被发现（Groisman & Steinberg 2000）。雷诺数保持极低（$Re < 0.1$）以消除任何惯性效应，确保任何存在的不稳定性纯属弹性质。当两种共动流体为牛顿流体时，界面是稳定的；但当使用聚合物溶液时，界面变得波动（Varshney & Steinberg 2019; David & Steinberg 2024）并呈现弹性湍流。压力谱显示出明显的转变，且谱衰减具有明确的形式（$S(P) \sim f^{-3.3}$），这是弹性湍流的典型特征。跨通道的压力降测量（$\Delta P$）显示，与纯粘性情况相比，阻力增加高达80%，并且表现出与压力谱测量一致的转变。这些测量使我们认识到，在稀聚合物流动中，即使雷诺数低至0.1，即使在平行剪切流和直通道中，也能激发弹性湍流。这一新发现颠覆了长达二十年的认知，即弹性湍流只能在流动中存在外部或内部施加的曲率/扰动时才能实现，并支持了最近日益增多的证据（Steinberg 2022），这些证据表明在具有弱扰动且无曲率的直通道中存在弹性湍流。

英文摘要：

As an experimental model to mimic the flow of bio-fluids in the cell and the flow in tiny blood capillaries, we study the co-moving shear flow of dilute polymeric solutions. An inflection point shear flow profile is created by parallel streams moving at different speeds inside a pressure-driven Hele-Shaw cell. The broad aim is to explore the possible instability mechanisms that lead to Elastic Turbulence, discovered two decades ago (Groisman & Steinberg 2000). The Reynolds number is kept very low ($Re < 0.1$) to eliminate any effects of inertia, ensuring that any present instabilities are purely elastic in nature. The interface is stable if the two co-moving fluids are Newtonian, but the interface becomes wavy (Varshney & Steinberg 2019; David & Steinberg 2024) and elastically turbulent with polymer solutions. Pressure spectra show clear transitions, and the spectral decays have a well-defined form ($S(P) \sim f^{-3.3}$), typical of Elastic Turbulence. Pressure drop measurements ($ΔP$) across the channel show an increase in drag up to 80% compared to the purely viscous case and exhibit transitions consistent with pressure spectra measurements. These measurements have led to an understanding that Elastic Turbulence in dilute polymeric flows can be excited at Reynolds numbers as low as 0.1, even with parallel shear flows and straight channels. This new finding overturns the two-decade understanding, that Elastic Turbulence could be achieved only in the presence of externally or internally imposed curvature/perturbation in the flow and supports the recent growing body of evidence (Steinberg 2022) which points to the presence of Elastic Turbulence in straight channels with weak perturbations and no curvatures.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑