Multiscale Approaches for the Dynamics and Rheology of Magnetic Fluids

首席研究员建议开展一项综合、全面的研究计划，该计划将理论和创新的数值方法与最先进的实验工作相结合，用于研究具有磁流体成分的两相系统。该项目旨在开发有效的预测计算工具，并推进对这些两相复杂（非牛顿）流的理解。虽然磁流体本身在技术上很重要，但它们也构成了一个很好的模型系统（由于它们的低维构型空间），用于复杂流体的科学研究以及主动悬架。因此，所提出的研究可以对更一般的具有复杂流体组分的两相流的多尺度建模和计算产生更广泛的影响。拟议工作的具体目标可概括如下：1)开发创新的、有效的二维和三维磁流体和含磁流体成分的两相流的微观宏观数值方法，并将其应用于这些复杂流体系统的动力学和流变学的预测和研究；2)使用专门针对的实验工作来验证新的计算方法，并为理论提供反馈机制；3)基于数值与实验相结合对磁流体系统流变学的进一步了解，建立简化模型；4)促进对磁场作用下影响磁流体液滴和乳剂（宏观）流变学的微观物理机制的基本理解。磁流体，也称为铁磁流体，是磁性纳米粒子在液体载体中的人造胶体悬浮液。由连续相包围的悬浮磁流体液滴组成的乳液在技术上具有重要的应用潜力，例如设计新的智能材料和药物靶向。为此，在聚合物和先进材料加工等其他应用中，有必要预测或操纵其液滴微观结构的动力学。这可以通过数学建模、计算机模拟和实验工作相结合来完成，研究者建议将这些工作作为本项目的一部分进行开发和整合。拟议活动的更广泛影响还包括教育、来自代表性不足群体的人的融合以及潜在的工业相关性。拟议的研究将在教育和培训新的计算数学学生骨干方面发挥核心作用，这些学生将学会在跨学科的国际团队中工作。

The Principal Investigator proposes to carry out an integrated, comprehensive research program which combines theory and innovative numerical methods with state of the art experimental work for the investigation of two-phase systems with a magnetic fluid component. This project aims at developing effective, predictive computational tools as well as to advancing the understanding of these two-phase, complex (non-Newtonian) flows. While magnetic fluids are technologically important on their own they also constitute an excellent model system (due to their low dimensional configuration space) for scientific study of complex fluids as well as for active suspensions. Consequently, the proposed research can have a wider impact in the multiscale modeling and computation of more general two-phase flows with a complex fluid component. The specific objectives of the proposed work can be summarized as follows: 1) to develop innovative, effective micro-macro numerical approaches for magnetic fluids and two phase flows with a magnetic fluid component in 2D and 3D and to apply them for the prediction and investigation of the dynamics and rheology of these complex fluid systems, 2) to use specifically targeted experimental work to validate the new computational approaches as well as to provide a feedback mechanism to the theory, 3) to formulate simplified models based on the an increased understanding of the rheology of magnetic fluid systems obtained by a combination of numerical and experimental work, and 4) to advance a fundamental understanding of the microphysical mechanisms that influence the (macro)rheology of magnetic fluid droplets and emulsions under the presence of a magnetic field.Magnetic fluids, also known as ferrofluids, are manmade colloidal suspensions of magnetic nano-particles in a liquid carrier. Emulsions consisting of suspended magnetic fluid droplets surrounded by a continuous phase offer a high potential for technologically important applications such as the design of new smart materials and drug targeting. To this end, as in other applications such as polymer and advanced material processing, it is necessary to predict or manipulate the dynamics of their droplet microstructure. This can be done with a combination of mathematical modeling, computer simulation, and experimental work which the investigator proposes to develop and integrate as part of this project. The broader impacts of the proposed activities also include education, the integration of people from underrepresented groups, and potential industrial relevance. The proposed research will play a central role in the education and training of a new cadre of computational math students who will learn to work in an interdisciplinary, international team.