Modeling and Computation of Flow-Structure Interaction in Multi-Phase and Complex Fluids

Ceniceros研究人员和合作者开发了两类现代的混合数值方法来研究二维和三维多相流的流固耦合作用，混合计算方法结合了两组通常不相交的方法，一方面是前沿捕获(通过水平集方法和基于相场的模型)和前沿跟踪(浸入边界设置)，另一方面是移动网格和自适应网格加密，以产生一种有效的方法，充分利用每种方法的最佳特性。此外，控制自适应前沿跟踪InConcert和领先的小尺度半隐式时间离散化被用来克服长期存在的与界面张力相关的时步问题(刚度)，所有这些因素的结合产生了完全自适应的非刚性混合方法，用于精确捕捉多相复杂流动中的小尺度效应、高界面变形和流-结构相互作用。了解流-结构相互作用如何影响多相流的宏观行为，具有重要的理论意义和实际意义。表面活性剂、粘弹性纤维、流体界面、聚合物微结构和纳米结构可以从根本上改变流动的行为，并最终决定复杂软物质配方的性质。这些方法是研究流动-结构相互作用的重要工具，这些问题与纳米技术、软性材料工业和一些生物医学应用直接相关。该项目还服务于一个重要的教育目标：本科生和研究生的跨学科教育和培养。

Ceniceros The investigator and collaborators develop two classes ofmodern, hybrid numerical methods to study fluid-structureinteraction for multi-phase flows in two and three dimensions.The hybrid computational methodologies merge two sets of usuallydisjoint approaches, front capturing (both through the level setmethod and through phase field based models) and front tracking(immersed boundary setting) on one hand, and moving meshes andadaptive mesh refinements on the other, to produce an efficientmethod that exploits the best features of each individualapproach. In addition, controlled adaptive front-tracking inconcert with a leading small-scales semi-implicit timediscretization is used to overcome the long-standing timestepping problem (stiffness) associated with interfacial tension.The blending of all these ingredients produces fully adaptiveand non-stiff hybrid methods for capturing accurately small-scaleeffects, high interfacial deformations, and flow-structureinteraction in multi-phase and complex flows. The understanding of how flow-structure interactioninfluences the macroscopic behavior of multi-phase flows is ofboth fundamental and practical significance. Surfactants,viscoelastic fibers, fluid interfaces, and polymericmicrostructures and nanostructures can radically change thebehavior of a flow and ultimately determine the properties ofcomplex soft matter formulations. The methodologies are animportant tool to study flow-structure interaction for a widevariety of problems of direct interest to nanotechnology, thesoft materials industry, and to some biomedical applications. Theproject also serves an important education goal: theinterdisciplinary education and training of undergraduate andgraduate students.