MRI: Acquisition of a High-Speed 3D Velocimetry System to Study Complex Flows

这个项目将促进我们对火灾蔓延、无人机设计、动脉瘤治疗、风力涡轮机和发动机开发、强风建筑设计、污染物扩散和水道生态系统管理的理解。这些不同主题的一个共同特征是它们强烈依赖于随时间迅速变化的复杂的三维流体流动。例如，动脉瘤的形成和破裂取决于动脉内不稳定的旋转血流所产生的压力。同样，大气污染的扩散也取决于湍流如何与污染物颗粒相互作用。这些领域的下一个突破需要能够在时间和空间上以高分辨率捕获这些3D流动的测量，这可以通过所获得的高速3D测速系统实现。这些设备将成为教师和学生的共享资源，并将大大提高广泛学科的研究质量。此外，这项令人兴奋的技术将用于吸引代表性不足的学生直接动手研究的机会。这种新仪器将提供数据收集能力，通过测量非定常3D速度和颗粒动力学，可以更深入地了解上述情况下的时变多相流。该系统使用激光照射流中放置或已经存在的示踪粒子，然后通过多个高速摄像机从不同视点记录粒子的图像来确定3D速度。这些数据将提供关于旋流、湍流-粒子相互作用、压力场和流体力的见解，揭示控制每个问题的潜在物理原理。获取非定常压力等数据，可以将压力与流动行为联系起来，从而为各种各样的问题提供大大改进的预测模型，包括开发下一代无人机机翼和风力涡轮机叶片，以及了解鱼类如何利用鱼群在湍流中航行。该系统还将大大提高我们对河流中泥沙颗粒如何影响水流湍流的认识，从而更好地预测侵蚀和沉积。此外，该仪器将用于捕捉湍流燃烧火焰的3D图像，通过紫外线透镜和过滤器测量燃烧气体排放，并从火焰的颜色和强度推断温度，从而实现效率和可持续性的突破。通过这些方式，新的高速测量系统将吸引来自一系列学科的研究人员，并对许多重要领域产生变革性影响。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 will advance our understanding of the spread of fires, the design of drones, the treatment of aneurysms, the development of wind turbines and engines, designs for buildings in high winds, the dispersion of pollutants, and management of waterway ecosystems. A common feature of these disparate topics is their strong dependence on complex, three-dimensional fluid flows that change quickly in time. For example, the formation and rupture of aneurysms depends on stresses created by the unsteady swirling blood flow inside arteries. Similarly, the spread of atmospheric pollution is governed by how turbulence interacts with the pollutant particles. The next breakthroughs in these fields require measurements that can capture these 3D flows with high resolution in time and space, made possible with the acquired High-Speed 3D Velocimetry System. This equipment will be a shared resource for faculty and students, and will greatly improve the quality of research in a wide array of disciplines. Moreover, this exciting technology will be used to engage underrepresented students directly in hands-on research opportunities.This new instrumentation will provide the capability for data collection that will support a deeper understanding of the time-varying, often multi-phase flows in the situations described above by measuring the unsteady 3D velocity and particle dynamics. The system uses lasers to illuminate tracer particles placed in or already present in a flow, then the 3D velocity is determined from multiple high-speed cameras recording images of the particles from different viewpoints. These data will provide insights on swirling flows, turbulence-particle interactions, pressure fields, and fluid forces, revealing the underlying physics governing each problem. Acquiring data, such as the unsteady pressure, will allow the stresses to be connected to the flow behavior, yielding greatly-improved predictive models for a wide variety of problems, including developing the next generation of drone wings and wind turbine blades, and understanding how fish use schooling to navigate turbulent flow. The system will also substantially advance our knowledge of how sediment particles in rivers affect flow turbulence to better predict erosion and deposition. Further, the instrumentation will be used to capture 3D images of flames in turbulent combustion, measure combustion-gas emissions via an ultraviolet lens and filters, and infer temperature from flame color and intensity, enabling breakthroughs in efficiency and sustainability. In these ways, the new high-speed measurement system will engage researchers from a range of disciplines and have a transformative impact on a number of important fields.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.