Collaborative Research: Hydrodynamic mechanisms for flow-induced self-assembly in confined complex fluids

CBET - 1603627; 1603806 PI：Blawzdziewicz，Jerzy; Loewenberg，Michael这个合作项目的目标是解释一个有趣的现象，当不混溶液体中的液滴在密闭空间中流动时，观察到这种现象。 在某些条件下，液滴排成一行，形成液滴链，这些液滴链持续存在，有时会合并形成细的液体束。 链的形成只观察到可变形的液滴的局限性乳液。 研究人员假设，由可变形液滴引起的流动的微小变化会诱导液滴成链排列。 将进行数值模拟，解决控制的变形的液滴和它们的运动在受限流的方程的假设进行测试。 通过改变材料参数，研究人员可以逐渐增加液滴变形的程度，这应该与链形成的程度相关。 该研究小组将与美国国家标准与技术研究所的一位研究人员合作，该研究人员首先通过实验观察到了连锁现象。 还将进行更多的实验，将数据与该项目中开发的计算机模拟进行比较。该团队希望了解导致液滴对齐的微尺度流动模式可以用来制造新的微结构材料。 研究人员将通过教学生编写简单的计算机程序来模拟流体中粒子的运动，让当地高中生参与耶鲁大学的科学之路项目。 他们还将为参加德克萨斯理工大学一个名为“科学：这是女孩的事”的夏令营的五年级到十一年级的女孩开发活动。“该项目将验证这样一个假设，即在强约束剪切流中由可变形的不混溶液滴产生的四极流场模式是在约束乳液中形成有序结构的原因。 将开发一个多粒子层次的计算机模拟算法，以确定引导粒子进入有序微观结构的关键流型。 负责微观结构形成的颗粒尺度现象将通过分析模拟结果并将其与高度受控条件下的实验进行比较来确定。 虽然该项目将集中在可变形滴乳液，该项目？的结果将适用于其他系统的自发有序与非线性粒子相互作用，如刚性粒子在非牛顿流体中的悬浮液。 了解约束流中自组装微结构的基本流体动力学机制可以帮助从业者设计和加工复合材料。

CBET - 1603627; 1603806PIs: Blawzdziewicz, Jerzy; Loewenberg, MichaelThe goal of this collaborative project is to explain an interesting phenomenon that is observed when liquid droplets in an immiscible liquid flow in confined spaces. For certain conditions, the droplets line up to form chains of drops that persist and sometimes coalesce to form thin liquid strands. Chain formation is only observed for confined emulsions of deformable drops. The investigators hypothesize that small changes in the flow, caused by the deformable drops, induce the drops to align in chains. The hypothesis will be tested by carrying out numerical simulations that solve the equations governing the deformation of the drops and their motion in confined flows. By varying material parameters, the investigators can gradually increase the extent of drop deformation, which should be correlated with the degree of chain formation. The research team will collaborate with a researcher at the National Institute of Standards and Technology who first observed the chaining phenomenon experimentally. Additional experiments will be carried out to compare data with the computer simulations developed in this project. The team expects that understanding the microscale flow patterns leading to drop alignment can be harnessed to make new microstructured materials. The researchers will engage local high school students in Yale's Pathway to Science Program by teaching students to write simple computer programs that simulate motions of particles in fluids. They will also develop activities for fifth through eleventh grade girls attending a residential summer camp at Texas Tech called "Science: It's a Girl Thing."The project will verify the hypothesis that quadrupolar flow-field patterns produced by deformable immiscible drops in a strongly confined shear flow are responsible for the formation of ordered structures in confined emulsions. A hierarchy of many-particle, computer simulation algorithms will be developed to identify key flow patterns that guide particles into ordered microstructures. Particle-scale phenomena responsible for the formation of microstructures will be determined by analyzing simulation results and comparing them with experiments under highly controlled conditions. Although the project will focus on emulsions of deformable drops, the project?s results will apply to spontaneous ordering in other systems with nonlinear particle interactions, such as suspensions of rigid particles in non-Newtonian fluids. Understanding the fundamental hydrodynamic mechanisms that govern self-assembling microstructures in confined flows could help practitioners design and process composite materials.