CAREER: Computational Infrastructures for Simulating Hygiene-Related Fluid Phenomena

每一种病原体都必须悬浮在一种特定的液体中才能在传播过程中存活下来。这些流体形式可以是散装液体、薄片、细丝、气泡、泡沫、液滴和气溶胶，所有这些都表现出混合维几何特征、高度非线性演化和巨大对比的尺度。 由于这些流体表现形式构成了物理世界中疾病传播的多样性，复杂性，在许多情况下是无形的途径，因此能够以高保真度模拟它们，并且这些模拟对公众的可访问性，不仅可以帮助家庭，学校和小企业解决他们的不同问题，而且还将为基础铺平道路。这项研究将开发计算基础设施，以模拟流体现象，如打喷嚏的粘液，飞溅的羽流和洗手泡沫，这些现象由于其交错的动态和几何复杂性而无法实现视觉和科学计算。项目成果将产生广泛的影响，使创造新颖的科学动画，教育插图和互动设计工具成为可能，共同支持一个包容性和可访问的平台，使科学家，工程师，医疗保健专业人员和STEM学生在高度个性化的环境中研究这些复杂的流程。这项研究将通过以下方式推进计算机图形学和科学计算的最新发展：建立了一套新的计算方法来处理以前研究不足或难以处理的流动现象。这些流体系统由不同的物质组成，例如粘液、唾液或生物表面活性剂，其表现出复杂的几何形状，例如薄膜、细丝、泡沫和极小的液滴，并且包含多物理过程，例如薄片破碎、涡旋-毛细管相互作用和流体接触。该项目旨在精确模拟复杂的界面流体现象，其特征在于0.1微米和1毫米之间的介观长度尺度上的薄，动态和非歧管流动特征。在该中间长度尺度下，流体由于表面张力和与其宏观或微观对应物显著不同的其他物理成分之间的相互作用而表现出复杂的流动动力学和几何形状（例如，流体可以反弹、行走、滑动、接触或形成常规方法难以模拟的非歧管泡沫结构）。这项工作将通过领导多方面的努力来弥合这一科学差距，开发新颖的几何数据结构，非流形界面跟踪算法，结构保持PDE规范配方，多相耦合方案和并行数值求解器，所有这些都将被整合到一个统一的模拟框架中，以促进广泛的卫生-该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Every pathogen must survive its transmission by suspending in a specific form of fluid. These fluid forms can be bulk liquids, thin sheets, filaments, bubbles, foams, droplets, and aerosols, all of which exhibit mixed-dimensional geometric features, highly nonlinear evolution, and vastly contrasting scales. Because these fluid manifestations constitute the diverse, complex, and in many cases invisible pathways for disease transmission in the physical world, the ability to simulate them with high fidelity, and the accessibility of these simulations to the public, would not only help families, schools, and small businesses solve their different problems but would also pave the way for fundamental advances in hygiene-related science. This research will develop the computational infrastructure to simulate fluid phenomena such as sneezing mucus, splash plumes, and hand-washing foam, which have been out of reach for visual and scientific computing due to their interleaving dynamic and geometric complexities. Project outcomes will have broad impact by making it possible to create novel scientific animations, educational illustrations, and interactive design tools, which jointly support an inclusive and accessible platform that allows scientists, engineers, healthcare professionals and STEM students to investigate these complex flow processes in highly individualized settings.This research will advance the state of the art in computer graphics and scientific computing by establishing a novel set of computational methods to tackle flow phenomena that were previously understudied or intractable. These fluid systems consist of different substances such as mucus, saliva, or biosurfactants, that exhibit intricate geometries such as thin films, filaments, foam, and extremely small droplets, and that encompass multi-physics processes such as thin sheet fragmentation, vortex-capillary interaction, and fluid contact. The project aims to enable the accurate simulations of complex interfacial fluid phenomena characterized by these thin, dynamic, and non-manifold flow features on the mesoscopic length scale between 0.1 micrometer and 1 millimeter. At this intermediate length scale, fluids exhibit complicated flow dynamics and geometric forms due to the interaction between surface tension and other physical ingredients which are remarkably different from their macroscopic or microscopic counterparts (for instance, fluid can bounce, walk, glide, contact, or form non-manifold foam structures which are difficult for conventional approaches to simulate). The work will bridge this scientific gap by leading multifaceted efforts to develop novel geometric data structures, non-manifold interface tracking algorithms, structure-preserving PDE gauge formulations, multiphase coupling schemes and parallel numerical solvers, all of which will be integrated into a unified simulation framework to boost a broad range of hygiene-related applications centered around these flow processes.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.