标题： 接近推进接触线的流动实验研究：理论模型的严格检验 显示英文标题

标题： An experimental study of flow near an advancing contact line: a rigorous test of theoretical models

摘要： 靠近移动接触线的流动取决于动态接触角、粘度比和毛细数。 我们报告了将平板浸入液体浴中的实验，同时使用数字图像处理和粒子图像测速技术测量界面形状、界面速度和流体流动。 所有实验均在低板速下进行，以保持小雷诺数和毛细数，以便与粘性理论进行比较。 在粘性相中测得的动态接触角保持在$90^{\circ}$以下，这是参数空间中尚未探索的区域。 本研究的重要目标是提供有价值的实验数据，以便开发和验证新的接触线模型。 界面形状显示，理论模型预测的强粘性弯曲在实验数据中并不存在。 流动场直接与\cite{huh1971hydrodynamic}的粘性理论预测进行了比较，但涉及弯曲界面的轻微修改。 在广泛的参数范围内，实验与理论之间发现了显著的一致性。 \cite{huh1971hydrodynamic}对界面速度的预测也与实验高度一致，仅在接触线附近除外。 发现界面沿材料点在接触线附近迅速减速，从而缓解了移动接触线处的奇异性。 据我们所知，此前尚未进行过如此详细的理论模型测试，我们希望本研究能推动该领域的新建模工作。 显示英文摘要

摘要： The flow near a moving contact line depends on the dynamic contact angle, viscosity ratio, and capillary number. We report experiments involving immersing a plate into a liquid bath, concurrently measuring the interface shape, interfacial velocity, and fluid flow using digital image processing and particle image velocimetry. All experiments were performed at low plate speeds to maintain small Reynolds and capillary numbers for comparison with viscous theories. The dynamic contact angle, measured in the viscous phase, was kept below $90^{\circ}$, an unexplored region of parameter space. An important aim of the present study is to provide valuable experimental data using which new contact line models can be developed and validated. Interface shapes reveal that the strong viscous bending predicted by theoretical models is absent in the experimental data. The flow field is directly compared against the prediction from the viscous theory of \cite{huh1971hydrodynamic} but with a slight modification involving the curved interface. Remarkable agreement is found between experiments and theory across a wide parameter range. The prediction for interfacial speed from \cite{huh1971hydrodynamic} is also in excellent agreement with experiments except in the vicinity of the contact line. Material points along the interface were found to rapidly slow down near the contact line, thus alleviating the singularity at the moving contact line. To the best of our knowledge, such a detailed test of theoretical models has not been performed before and we hope the present study will spur new modeling efforts in the field.