CBET-EPSRC: Dynamic Wetting & Interfacial Transitions in Three Dimensions: Theory vs Experiment

该项目是通过“化学、生物工程、环境和运输系统司、土木工程、机械和制造创新司以及电气、通信和网络系统司--英国工程和物理科学研究理事会(ENG-EPSRC)牵头机构活动下提交合作建议书的特别指导方针”授予的。液体在固体表面上稳定扩散的最大速度是决定许多自然和技术过程结果的关键因素。当超过动态润湿的最大速度时，出现的不稳定会产生复杂的三维流动，这通常是不受欢迎的。例如，在涂覆涂料时，可能会将不需要的气泡带入液体中，严重限制了各种产品的生产速度。更好地了解这种不稳定性对于开发提高动态润湿最大速度的策略至关重要，这将有助于许多实际应用。该项目采用实验分析和计算模拟相结合的方法，显著提高了对超过最大动态润湿速度时产生的复杂三维流动的基本理解。明尼苏达双城大学的这项拟议研究将与华威大学的研究人员合作，通过以下方式在解决动态湿润领域的长期问题方面取得重大进展：(I)开发能够捕捉3D现象的用户友好的多尺度计算框架；(Ii)使用分析和计算建模来表征和了解动态湿润线的稳定性；以及(Iii)利用计算能力和实验研究来表征和理解控制液滴动态的界面不稳定性。计算建模的关键进展将是为有限元方法开发一种动态网格生成能力，这种能力可以精确地求解三维时间相关流动。实验将在定制的镀膜装置中进行，包括通过流动显示测量动态润湿的最大速度和不稳定波长，以及通过干涉测量携带气膜的厚度。该项目所产生的知识有望刺激基础研究的新方向，并使许多自然和技术过程受益，其中动态润湿起着关键作用。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project was awarded through the "Special Guidelines for Submitting Collaborative Proposals under the Division of Chemical, Bioengineering, Environmental, and Transport Systems, the Division of Civil, Mechanical and Manufacturing Innovation, and the Division of Electrical, Communications and Cyber Systems - the UK Engineering and Physical Sciences Research Council (ENG-EPSRC) Lead Agency Activity" opportunity. The maximum speed at which a liquid can spread stably over a solid surface is the key factor to determining the outcomes of numerous natural and technological processes. The instability that emerges when this maximum speed of dynamic wetting is exceeded creates complex three-dimensional flows that are typically undesirable. For example, undesirable air bubbles can be entrained into the liquid while applying a coating, severely limiting the rate of manufacture of a wide range of products. Improved understanding of this instability is essential for developing strategies to increase the maximum speed of dynamic wetting, which will benefit many practical applications. This project uses a combination of experimental analysis and computational modelling to significantly advance fundamental understanding of the complex three-dimensional flows that arise when the maximum speed of dynamic wetting is exceeded. User-friendly software will be developed that others can apply to understand numerous other problems involving dynamic wetting that arise in areas such as climate science.The proposed research at the University of Minnesota-Twin Cities, in collaboration with researchers at the University of Warwick, will make significant progress in resolving longstanding issues in the area of dynamic wetting by (i) development of a user-friendly multiscale computational framework capable of capturing 3D phenomena, (ii) use of both analysis and computational modelling to characterize and understand the stability of dynamic wetting lines, and (iii) use of both computational capabilities and experimental investigations to characterize and understand interfacial instabilities governing the dynamics of droplets. The key advance of the computational modeling will be the development of a dynamic mesh generation capability for finite-element methods that can accurately resolve three-dimensional time-dependent flows. The experiments will be conducted in a custom-made coating apparatus, and will involve measurements of the maximum speed of dynamic wetting and instability wavelength by flow visualization, as well as measurements of the thickness of entrained air films by interferometry. The knowledge generated from this project is expected to stimulate new directions of fundamental research and to benefit numerous natural and technological processes in which dynamic wetting plays a key role.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.