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，将理论和创新的数值方法与最先进的实验工作相结合，以研究具有磁性流体成分的两相系统。该项目旨在开发有效的、可预测的计算工具，以及促进对这些两相、复杂(非牛顿)流动的理解。虽然磁性流体本身在技术上很重要，但它们也构成了一个优秀的模型系统(由于它们的低维构型空间)，用于复杂流体的科学研究以及活性悬浮液。因此，所提出的研究可以对具有复杂流体组分的更一般的两相流动的多尺度建模和计算产生更广泛的影响。所提议的工作的具体目标可以概括如下：1)开发创新的、有效的微观-宏观数值方法，用于2D和3D中的磁性流体和具有磁性流体组分的两相流动，并将其应用于预测和研究这些复杂流体系统的动力学和流变性；2)使用专门有针对性的实验工作来验证新的计算方法以及为理论提供反馈机制；3)基于通过数值和实验工作的组合获得的对磁性流体系统的流变性的更多了解来建立简化模型，4)加深对磁场作用下影响磁性液体液滴和乳状液(宏观)流变性的微观物理机制的基本理解。磁性液体，也称为磁流体，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性液体液滴组成的乳状液在设计新型智能材料和药物靶向等重要技术应用方面具有很高的潜力。为此，与聚合物和先进材料加工等其他应用一样，有必要预测或操纵其液滴微结构的动力学。这可以通过数学建模、计算机模拟和实验工作的组合来完成，研究人员建议将这些工作作为该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入以及潜在的产业相关性。拟议的研究将在教育和培训一批新的计算数学学生干部方面发挥核心作用，他们将学习在一个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.