Fluid-structure interactions between non-Newtonian viscoelastic fluids and flexible cylinders

非牛顿粘弹性流体与柔性圆柱体之间的流固相互作用

• 批准号: 1705251
• 负责人: Yahya Modarres-Sadeghi
• 金额: $ 46.18万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-15 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1705251&HistoricalAwards=false
• 关键词: Fluid; structure; interactions; between; non

The goal of the proposed research is to study the interactions that occur between a flexible or flexibly-mounted structure and the elastic instabilities that can result from the flow of a non-Newtonian viscoelastic fluid past that structure. A host of Fluid-Structure Interactions (FSI) studies have been performed with Newtonian fluids; however, no viscoelasticity-induced FSI studies of non-Newtonian fluids have been performed previously. As a result, a comprehensive understanding of these vicoelastic FSI phenomena is both intriguing from a fundamental scientific point of view and essential for a number of biological and industrial applications, with potentials of being transformative to the field of FSI. A fundamental understanding of FSI between viscoelastic fluids and flexible structures has great potentials for improving manufacturing techniques used for carbon fiber reinforced polymer composites where often a polymer resin is driven through a cluster of carbon fibers. The findings of this research will be disseminated at different levels by integrating the proposed research into the outreach programs for K12 students and teachers, and by increasing research opportunities for students.When a flexibly-mounted bluff body (such as a circular cylinder) is placed in Newtonian flows, the shedding of separated vortices at high Reynolds numbers can drive the motion of the structure. This phenomenon is known as Vortex-Induced Vibration (VIV) and has been studied extensively. If the same flexibly-mounted circular cylinder is placed in non-Newtonian flows, however, the structure's response is unknown. Unlike Newtonian fluids, the flow of viscoelastic fluids can become unstable at infinitesimal Reynolds numbers. For non-Newtonian flows around a fixed circular cylinder, purely elastic flow instabilities have been observed. The research will focus on the response of flexible or flexibly-mounted structures to forces from non-Newtonian flows. Two classes of fluids will be used in the study. For wormlike micelle solutions, the flow instabilities occur downstream of the cylinder, and for polymer solutions the flow instabilities occur upstream of the cylinder. To relate the findings to several important applications, FSI tests will be conducted at a micro scale by considering the interactions between flexible hydrogel beams and the forces of polymer solutions. In each test, a wide range of flow velocities will be covered, before and after the flow instability, and the structure's displacement will be measured at each step. Velocimetry and flow-induced birefringence measurements will be taken in order to quantify the influence of the structural oscillations on the flow instabilities.

拟议的研究的目标是研究之间发生的相互作用，一个灵活的或灵活安装的结构和弹性不稳定性，可以导致从一个非牛顿粘弹性流体的流动过去的结构。大量的流体-结构相互作用（FSI）的研究已经进行了牛顿流体，但是，没有粘弹性诱导的FSI研究的非牛顿流体已经进行过。因此，从基础科学的角度来看，对这些粘弹性FSI现象的全面理解是有趣的，并且对于许多生物和工业应用是必不可少的，具有变革FSI领域的潜力。粘弹性流体和柔性结构之间的流固耦合的基本理解具有很大的潜力，用于改善碳纤维增强聚合物复合材料的制造技术，其中通常聚合物树脂被驱动通过一簇碳纤维。本研究的成果将通过将建议的研究纳入K12学生和教师的推广计划，并通过增加学生的研究机会，在不同层面上传播。当柔性安装的海崖体（如圆柱体）放置在牛顿流中时，在高雷诺数下分离涡的脱落可以驱动结构的运动。这种现象被称为涡激振动（VIV），并已被广泛研究。然而，如果同样的柔性安装的圆柱体被放置在非牛顿流中，则结构的响应是未知的。与牛顿流体不同，粘弹性流体的流动在无穷小的雷诺数下会变得不稳定。对于绕固定圆柱的非牛顿流动，已经观察到纯弹性流动不稳定性。 研究将集中在柔性或柔性安装结构对非牛顿流力的响应。本研究将使用两类液体。对于蠕虫状胶束溶液，流动不稳定性发生在圆柱体的下游，而对于聚合物溶液，流动不稳定性发生在圆柱体的上游。为了将这些发现与几个重要的应用联系起来，FSI测试将通过考虑柔性水凝胶梁与聚合物溶液的力之间的相互作用在微观尺度上进行。在每一个测试中，将涵盖广泛的流速范围，在流动不稳定之前和之后，并在每一步测量结构的位移。为了量化结构振荡对流动不稳定性的影响，将进行测速和流致双折射测量。

项目成果

Viscoelastic fluid-structure interactions between a flexible cylinder and wormlike micelle solution

• DOI: 10.1103/physrevfluids.3.063301
• 发表时间: 2018-06-11
• 期刊: PHYSICAL REVIEW FLUIDS
• 影响因子: 2.7
• 作者: Dey, Anita A.;Modarres-Sadeghi, Yahya;Rothstein, Jonathan P.
• 通讯作者: Rothstein, Jonathan P.

Oscillations of a cantilevered micro beam driven by a viscoelastic flow instability

• DOI: 10.1039/c9sm01794a
• 发表时间: 2020-02-07
• 期刊: SOFT MATTER
• 影响因子: 3.4
• 作者: Dey, Anita A.;Modarres-Sadeghi, Yahya;Rothstein, Jonathan P.
• 通讯作者: Rothstein, Jonathan P.