Swirling Propulsion in Complex Fluids and Micro-Swimming Rheometry

复杂流体中的旋流推进和微游动流变测量

• 批准号: 2210532
• 负责人: Eric Stefan Shaqfeh
• 金额: $ 44.7万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-15 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2210532&HistoricalAwards=false
• 关键词: Swirling; Propulsion; Complex; Fluids; Micro

The movement of micro-organisms is often complicated by the complexity of the fluids in which they reside. Many of the fluids (e.g., mucous) in which these organisms “swim” contain large macromolecules such as proteins that limit successful swimming. It is more difficult to swim through these “sticky” fluids. It has recently been suggested theoretically that a type of microbial swimming called “swirl” can create propulsion in complex liquids that would not be possible in “simple,” less sticky fluids. Swirl is characterized by parts of the body spinning around the axis of an axisymmetric body. Swirl is a key feature of the swim stroke of many micro-organisms. This award will develop a novel micro-robot that demonstrates the characteristics of swirl propulsion in complex fluids and uses that propulsion to measure the properties of the surrounding fluid. Thus, it is a dynamic sensor of complex fluid properties or a “swimming rheometer”. Standard rheometers are desktop devices where fluid is brought to the device and the native environment of the fluid application is reproduced in the device. The state of stress in the shear flow of complex fluids requires the measurement of at least three material properties as a function of the shear rate in the fluid. The goal in the present award is that through design, miniaturization, and optimization of a newly developed “swirling” robot, rheometry will be transformed to a remote, in situ sensing science. Thus, one will bring the “rheometer to the fluid application” rather than bringing a fluid sample to a fixed rheometer. A tennis ball-size prototype has already been created and the primary concepts are successfully demonstrated. The robot was designed and will continue to be optimized via large scale computer simulation. The miniaturized robot will have immediate medical and biological applications including measuring the complex rheological properties of synovial fluid as a direct mapping to several disease conditions. Moreover, multiple miniaturized robots will be used to examine the collective dynamics of these micro-swirlers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

微生物的运动常常因其所处流体的复杂性而复杂化。这些生物“游泳”的许多液体（如粘液）含有诸如蛋白质之类的大分子，这些大分子限制了它们成功游泳。在这些“粘稠”的液体中游泳更加困难。最近有人从理论上提出，一种被称为“漩涡”的微生物游泳可以在复杂的液体中产生推进力，这在“简单”、粘性较低的液体中是不可能的。旋流的特点是身体的部分围绕轴对称身体的轴旋转。旋流是许多微生物游泳动作的一个关键特征。该奖项将开发一种新型微型机器人，该机器人将展示复杂流体中的涡流推进特性，并利用这种推进来测量周围流体的特性。因此，它是一种复杂流体特性的动态传感器或“游泳流变仪”。标准流变仪是台式设备，流体被带到设备中，流体应用的原生环境在设备中重现。复杂流体剪切流动中的应力状态要求测量流体中作为剪切速率函数的至少三种材料特性。本奖项的目标是通过设计、小型化和优化新开发的“旋转”机器人，将流变学转变为远程、原位传感科学。因此，人们将带“流变仪到流体应用”，而不是带流体样品到固定的流变仪。一个网球大小的原型已经被制造出来，基本概念已经成功地展示出来。该机器人已经设计完成，并将通过大规模计算机模拟继续进行优化。这种微型机器人将有直接的医学和生物应用，包括测量滑液的复杂流变特性，作为几种疾病状况的直接映射。此外，将使用多个小型化机器人来检查这些微型旋流器的集体动力学。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。