CAREER: Fluid-Structure Interactions in Pulsatile Flow

该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术容易过早衰竭，一个反复出现的挑战是对血液脉动流动如何与心脏瓣膜叶相互作用并影响其长期耐用性的有限了解。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的影响相关的流动物理。除了能够改进心脏瓣膜设计外，研究成果还将使学术界和工业界的大量工程师和科学家受益，他们研究自然飞行、生物力学、航空学、可再生能源、空间探索等多个学科的流体-结构相互作用物理。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，为K-12学生举办外联讲习班；以及(3)针对公众，采用基于虚拟现实的教育工具。该项目的总体目标是开发一个专注于流体-结构相互作用的综合研究和教育计划，该计划将揭示基于标度定律的基本流动物理，用于脉动流动中柔性膜(例如心脏瓣膜)的颤动。为此，该项目将首次在高保真实验流体-结构相互作用测量(使用光场成像)中建立一个新的范例，以同时量化时间分辨的3D流场和相关的结构运动或应变。这种新的验证实验方法将被用来收集测量数据，以得出独特的可缩放参数，以分类脉动流中的颤振模式，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体-结构相互作用的合理标度定律的理解；以及(2)用于计算验证的高保真实验流体-结构相互作用测量的广泛数据库。这种流体-结构相互作用物理量化的改进和比例定律的发展将使更好地预测颤动导致的疲劳故障，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NSF的法定使命，并通过使用基金会的智力优势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.