Walls Peter L L, Dequidt Grégoire, Bird James C
Department of Mechanical Engineering, Boston University , Boston, Massachusetts 02215, United States.
École Polytechnique , 91128 Palaiseau, France.
Langmuir. 2016 Apr 5;32(13):3186-90. doi: 10.1021/acs.langmuir.6b00351. Epub 2016 Mar 24.
When a capillary tube is brought into contact with a wetting liquid, surface tension forces overcome gravity and the liquid spontaneously rises into the tube until an equilibrium height is reached. The early viscous dynamics of the rise typically follow the well-known Lucas-Washburn law, which is independent of gravity and neglects the displaced fluid. Here we explore the early viscous dynamics when the properties of displaced fluid are significant. Using a combination of experiments and theory, we show how the characteristic behavior of the Lucas-Washburn law is modified when the viscosity of the displaced fluid is comparable to or exceeds the wetting fluid. Additionally, we find that the effects of gravity reshape the dynamics of the capillary rise not only in the late viscous regime but also in the early viscous regime.
当一根毛细管与一种可湿润液体接触时，表面张力会克服重力，液体自发地上升到管中，直至达到平衡高度。上升过程早期的黏性动力学通常遵循著名的卢卡斯 - 沃什伯恩定律，该定律与重力无关且忽略了被置换的流体。在此，我们探讨当被置换流体的性质显著时的早期黏性动力学。通过实验与理论相结合的方法，我们展示了，当被置换流体的黏度与可湿润流体相当或超过可湿润流体时，卢卡斯 - 沃什伯恩定律的特征行为是如何被改变的。此外，我们发现重力的影响不仅在黏性后期阶段，而且在黏性早期阶段都会重塑毛细管上升的动力学。
