CAREER: Drop impact dynamics and fingering on thin liquid films

职业：液体薄膜上的跌落冲击动力学和指法

• 批准号: 2338362
• 负责人: Solomon Adera
• 金额: $ 54.98万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2028-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2338362&HistoricalAwards=false
• 关键词: CAREER; Drop; impact; dynamics; fingering

Engineers, physicists, and the general public have been fascinated by the beautiful images of the crown that forms when a drop impacts a rigid surface. Besides the mesmerizing images, drop impact, spreading, retraction, and breakup has broad technological implications in agriculture, inkjet and microelectronics printing, spray coating, combustion, energy generation, and forensic science. Despite the many utilities, drop impact dynamics on thin liquid films is not fully understood to date due to (a) the complex interplay between surface tension, viscosity, inertia, and gravity and (b) the challenge of coating surfaces with precisely controlled sub micrometer liquid layers. Recent advances in micro/nanofabrication have enabled this by manipulating fluid-structure interaction. The principal aim of the research program is to provide fundamental understanding of drop impact on thin liquid films. The project will encompass closely integrated education and outreach programs including multi-year student mentoring at the undergraduate and graduate levels and a community outreach to motivate, inspire, and enrich the educational experience of K-12 students through two major public venues: University of Michigan Museum of Natural History and Xplore Engineering.The goal of the research program is to use experiments and theoretical modeling to develop a comprehensive understanding of drop impact dynamics on thin liquid films where the liquid layer thickness is less than one micron. Using state-of-the-art micro/nanoengineered surfaces coated with a lubricant film of known thickness, the research program investigates drop impact dynamics with three principal objectives: 1) understanding the role of air entrapment when a drop impacts a smooth and deformable liquid film featuring liquid-liquid contact between the drop and the lubricant coating, 2) identifying the role of the annular wetting ridge on fingering and drop breakup, and 3) understanding the root cause of the hydrodynamic instability that ensues impact and the number of satellite drops that bifurcate from the radially expanding liquid lamella. The research aims to capture the effects of density and viscosity mismatch between the drop and the lubricant layer on the breakup mechanism. By combining high-speed visualization, fluorescence microscopy, white light interferometry, reflection interference contrast microscopy, and planar laser-induced fluorescence, the proposed research is expected to produce new knowledge and guide future research in soft matter physics and fluid mechanics.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.

工程师、物理学家和公众都对水滴撞击刚性表面时形成的美丽的皇冠图像着迷。除了令人着迷的图像之外，跌落冲击、扩散、回缩和破碎在农业、喷墨和微电子印刷、喷涂、燃烧、能源产生和法医学方面也具有广泛的技术意义。尽管有许多实用程序，但由于 (a) 表面张力、粘度、惯性和重力之间复杂的相互作用以及 (b) 用精确控制的亚微米涂层表面的挑战，迄今为止尚未完全了解液滴对薄液膜的冲击动力学液体层。微/纳米制造的最新进展通过操纵流体-结构相互作用实现了这一点。该研究计划的主要目的是提供对液滴对液膜影响的基本了解。该项目将涵盖紧密结合的教育和外展计划，包括本科生和研究生级别的多年学生辅导以及社区外展，以通过两个主要公共场所激励、启发和丰富 K-12 学生的教育体验： 密歇根大学自然历史博物馆和 Xplore 工程。该研究项目的目标是利用实验和理论建模来全面了解液体层厚度小于一微米的薄液膜上的液滴冲击动力学。该研究项目使用涂有已知厚度润滑膜的最先进的微/纳米工程表面，研究液滴冲击动力学，其三个主要目标是：1）了解当液滴冲击光滑且可变形的液体时，空气滞留的作用薄膜以液滴和润滑剂涂层之间的液-液接触为特征，2) 确定环形润湿脊对指状和液滴破碎的作用，以及 3) 了解随之而来的冲击和数量的流体动力学不稳定的根本原因从径向膨胀的液层中分叉出来的卫星液滴。该研究旨在捕捉液滴和润滑层之间的密度和粘度不匹配对破碎机制的影响。通过结合高速可视化、荧光显微镜、白光干涉测量、反射干涉对比显微镜和平面激光诱导荧光，该研究有望产生新知识并指导软物质物理和流体力学的未来研究。该奖项反映了通过使用基金会的智力价值和更广泛的影响审查标准进行评估，NSF 的法定使命被认为值得支持。