CBET-EPSRC: Droplet Impact on Fluid Interfaces: 3D Effects Across Scales

在过去的几十年里，人们一直对液滴冲击问题的解释有着持久而广泛的兴趣。在目前的工作中，我们提出了一个综合实验，数值和分析研究液滴对流体界面的影响，重点是三维效应。可以说，由于流体流动的高度多尺度性质和强烈的非线性界面变形，精确研究三维冲击所需的算法和相关计算能力近年来才刚刚开始成熟。同样，可视化和流量测量方面的最新进展也使得在实验室中进行此类研究成为可能。我们雄心勃勃的项目汇集了流体动力学领域的各种年轻领导者，以解决这一令人兴奋和紧迫的研究课题，并开发新的变革性框架，以尖端的工具和方法研究这一具有挑战性的问题。液滴-液体影响是一系列工业应用的基础，如喷雾冷却、燃油喷射、农业应用（如农药喷洒、雨滴影响）、传染病传播、制造应用（如喷墨打印和基于液滴的3D打印）以及环境应用（如溢油修复）。由于实验表征和可视化相对简单，并且减少了计算需求，因此之前关于液滴-液体和液滴-固体撞击的大部分工作都集中在轴对称，正常撞击上。实际上，非轴对称的液滴界面影响更为常见，因此扩大目前的理解，包括明确的三维效应，对于解锁和推进应用具有关键和及时的重要性。在每个组成研究的目标将集中在描述参数阈值之间的冲击制度的反弹，聚结，和飞溅。这些努力将伴随着低阶模型的发展（由实验和高保真仿真指导和基准），以扩展我们结果的实际适用性。本文提出的高度协作的研究计划将在单一框架下完全跨越低能到高能撞击，并允许为液滴撞击同一流体的液体层开发单一、一致的物理图像，前所未有地关注三维效应、环境气体的作用和流体层的深度。预计研究成果不仅包括具体的科学发现，还包括基准和记录的实验和计算工具和数据集，以加强该领域广泛的全球研究工作。此外，pi将联合开发新的实验和模拟数据可视化活动，以促进英国和美国的科学、推广目的和访问倡议。几位知名艺术家已经同意参加流体可视化活动、公开工作室会议和比赛，这些活动将由pi组织，以他们在科学可视化方面的集体成功记录为基础。

Over the past several decades there has been persistent and broad interest in the elucidation of drop impact problems. In the present work, we propose an integrated experimental, numerical, and analytical investigation of droplet impact on fluid interfaces with a focus on three-dimensional effects. Arguably, the required algorithms and associated computing power needed to accurately investigate 3D impacts are only just starting to mature in recent years due to the highly multi-scale nature of the fluid flow and strongly non-linear interfacial deformations. Similarly, recent advances in visualization and flow measurement have now made such investigations possible in the lab. Our ambitious project brings together a diverse set of young leaders in fluid dynamics to tackle this exciting and pressing research topic, and develop new transformative frameworks to study this challenging set of problems with cutting-edge tools and methodologies. Droplet-liquid impacts are fundamental to a range of industrial applications such as spray cooling, fuel injection, agricultural applications such as pesticide spray, and rain droplet impact, infectious disease transmission, manufacturing applications such as inkjet printing and droplet-based 3D printing, and environmental applications such as oil spill remediation. The bulk of prior work on droplet-liquid and droplet-solid impact focuses on axisymmetric, normal impacts due to the relative simplicity of experimental characterization and visualization and reduced computational demands. In practice, non-axisymmetric droplet-interface impacts are far more common and thus broadening the current understanding to include explicit three-dimensional effects is of critical and timely importance to unlocking and advancing applications. The objective in each constituent study will be focused on delineating parametric thresholds between the impact regimes of rebound, coalescence, and splashing. These efforts will be accompanied by the development of reduced-order models (guided and benchmarked by experiment and high-fidelity simulation) to extend the practical applicability of our results. The highly collaborative research program proposed herein will fully span low-energy to high-energy impacts under a single framework and allow the development of a single, consistent, physical picture for droplet impacts on liquid layers of the same fluid, with an unprecedented focus on three-dimensional effects, the role of the ambient gas, and the depth of the fluid layer. The research outputs are anticipated not only to include the specific scientific discoveries, but also benchmarked and documented experimental and computational tools and datasets to strengthen the broad global research efforts in the area.Moreover, the PIs will jointly develop new experimental and simulation data visualization activities related to the proposed work for the promotion of science, outreach purposes, and access initiatives in both the UK and USA. Several established artists have agreed to participate in visualisation of fluids events, open studio sessions and competitions, which will be organised by the PIs, building on their collective record of success in scientific visualisation.