Innovative methods for the dynamics of immersed structures in complex fluids

研究人员和合作者建议开发一类新的基于浸没边界的方法来研究大量二维和三维浸没结构与复杂(非牛顿)流体的相互作用。这些创新的方法将具有复杂流体中一些突出的、令人敬畏的流动-结构相互作用问题所要求的计算效率，并将在这类系统的建模和模拟中建立新的范例。为了实现这一点，研究人员和项目参与者将引入根本上的创新方法，用于快速计算结构对流动的影响，快速求解稳健的隐式离散，以及在重要应用中存在复杂流体的情况下进行建模和计算。虽然新方法的设计将考虑到具体的问题(复杂流体中的精子集体运动和蠕动泵送)，但它们的适用性将是广泛的。无数技术和科学上的重要问题可以描述为流动和浸入结构的相互作用，这些结构可以是弹性的或刚性的，可能有从纳米到宏观的各种形状和长度尺度。微生物的游动，如细胞和鞭毛的运动，精子的运动，昆虫的飞行，空气动力学设计，心脏流体动力学，以及聚合物材料的加工，只是几个重要的例子。现在有一个公认的迫切需要在更现实的流体环境中研究这些动力学，考虑到潜在复杂流动的频繁粘弹性特征。该项目的重点是开发流体模型和有效的计算工具来研究这类重要的问题。将在多学科环境中大力整合研究和教育，持续努力促进和扩大代表性不足群体的参与，本科生的积极参与，创新的教学举措和合作模式，以及与工业部门的联系。

The investigator and collaborators propose to develop a new class of Immersed Boundary-based methods to investigate the interaction of a large number of immersed structures in 2D and 3D with a complex (non-Newtonian) fluid. These innovative methods will have the computational efficiency demanded by some outstanding, formidable problems of flow-structure interaction in complex fluids and will establish new paradigms in the modeling and simulation of these type of systems. To achieve this, the investigator and the project's participants will introduce fundamentally innovative approaches for the fast computation of the influence of the structure on the flow, for the rapid solution of robust, implicit discretizations, and for model building and computation in the presence of a complex fluid in important applications. While the new approaches will be designed with concrete problems in mind (collective sperm motility in a complex fluid and peristaltic pumping), their applicability will be broad.A myriad of technologically and scientifically important problems can be described as the interaction of a flow and immersed structures that could be elastic or rigid and could come in a broad range of shapes and length scales, from nano to macro. The swimming of micro-organisms like cellular and flagellar locomotion, sperm motility, insect flight, aerodynamic design, cardiac fluid dynamics, and processing of polymeric materials are just a few important examples. There is now a recognized, pressing need to investigate these dynamics in more realistic fluid environments which take into account the frequent viscoelastic character of the underlying complex flow. The project focuses on the development of fluid models and efficient computational tools to investigate this important class of problems. Research and education will be vigorously integrated in a multi-disciplinary environment with a sustained effort to promote and broaden the participation of underrepresented groups, with the active participation of undergraduates, with innovative pedagogic initiatives and modes of collaboration, and with ties with the industrial sector.