CAREER: Fluid-Structure Interactions in Pulsatile Flow

这个项目的动机是迫切需要为全球老龄化人口的心血管健康设计持久的解决方案和设备。由于现有的心脏瓣膜置换容易过早衰竭，一个反复出现的挑战是对脉冲血流如何与心脏瓣膜小叶相互作用并影响其长期耐久性的理解有限。通过利用3D成像技术的最新进展，该项目旨在揭示与脉冲流动对柔性材料疲劳破坏影响相关的流动物理。除了改进心脏瓣膜设计之外，研究成果将使学术界和工业界的大量工程师和科学家受益，他们研究跨多个学科的流固相互作用物理，如自然飞行，生物力学，航空学，可再生能源，太空探索等。综合教育计划采用三管齐下的方法，包括：(1)实施新颖的基于游戏的学习技术，以提高大学教育和研究的参与度；(2)针对STEM中代表性不足的学生的K-12外展讲习班；(3)采用面向公众的基于虚拟现实的教育工具。该项目的总体目标是建立一个专注于流体结构相互作用的综合研究和教育计划，该计划将揭示脉动流（例如心脏瓣膜）中柔性膜颤振的基于缩放定律的基本流动物理。为此，该项目将首次建立高保真实验流固相互作用测量（使用光场成像）的新范式，同时量化时间分辨的3D流场和相关的结构运动或应变。新的验证实验方法将用于收集测量数据，以获得独特的可扩展参数，以分类脉动流动中的颤振机制并确定相关的流动物理机制。一些预期的研究成果包括：(1)对脉动流动中柔性膜的流固相互作用有一个完善的基于尺度定律的理解；(2)一个广泛的高保真实验流固耦合测量数据库，用于计算验证。这种改进的流固相互作用物理量化和标度定律的发展将能够更好地预测颤振引起的疲劳失效，这是提高生物心脏瓣膜置换寿命的关键一步。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。

This project is motivated by a critical need to engineer durable solutions and devices for the cardiovascular health of a global aging population. With existing heart valve replacements vulnerable to premature failure, a recurring challenge is the limited understanding of how the pulsing flow of blood interacts with the heart valve leaflets and affects its long-term durability. By exploiting recent advances in 3D imaging technologies, this project aims to uncover the flow physics relating the influence of a pulsing flow on the fatigue failure of flexible materials. In addition to enabling improved heart valve designs, the research outcomes will benefit a large community of engineers and scientists both in academia and industry who study fluid-structure interaction physics across multiple disciplines such as - natural flight, biomechanics, aeronautics, renewable energy, space exploration, among others. The integrated education plan adopts a three-pronged approach including: (1) implementation of novel game-based learning techniques to improve engagement in university education and research; (2) outreach workshops for K-12 aimed at underrepresented students in STEM; and (3) the adoption of Virtual Reality based education tools aimed at the public.The overall goal of this project is to develop an integrated research and education program focused on fluid-structure interactions that will reveal scaling laws-based fundamental flow physics for flutter of flexible membranes in a pulsatile flow (e.g., heart valves). To this end, for the first time, this project will establish a new paradigm in higher-fidelity experimental fluid-structure interaction measurements (using light-field imaging) to simultaneously quantify time-resolved 3D flow fields and the associated structural motion or strain. The novel validated experimental method will be used to gather measurements to derive unique scalable parameters to classify regimes of flutter in pulsatile flow and identify the associated flow physics mechanisms. Some of the anticipated research outcomes include: (1) a sound scaling laws-based understanding of fluid-structure interaction of flexible membranes in pulsatile flow; and (2) an extensive database of high-fidelity experimental fluid-structure interaction measurements for computational validation. Such improved quantification of fluid-structure interaction physics and development of scaling laws will enable better prediction of flutter-induced fatigue failure, a key step towards improving longevity of biological heart valve replacements.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.