MRI: Acquisition of an Integrated High Frame-Rate Particle Image Velocimetry (HFR-PIV) System

本MRI项目资金用于获取集成的高帧率粒子图像测速（HFR-PIV）系统，以获得各种湍流中的高分辨率，时间分辨，全场，定量实验数据。在HFR-PIV系统开发之前无法实现的时间分辨全场流测量有可能极大地推进我们对流动物理的理解，并将在创建先进的模拟工具中发挥重要作用，例如用于大涡模拟的亚网格尺度过程的参数化。HFR-PIV也将成为NSF epscor资助的大型设施中用于开发和测试高雷诺数湍流边界层流动的传感、预测、驱动和控制技术的关键测量技术（Klewicki et al. 2006）。该仪器将供主要研究人员及其研究小组、从事实验流体动力学的其他UNH研究人员以及新研究生实验课程的学生使用。智力优势：该工具允许在其时间演变的背景下理解空间结构。这种能力是阻碍我们理解复杂流体现象的主要障碍。例如，空化流动中液相和气相的高帧率PIV将首次在大量定性工作（高速摄影、视频）和定量流动测量之间架起一座桥梁。在湍流边界层中，推进输运机制的当前知识状态需要流场信息，这些信息可以捕获动态运动随时间演变的跨空间尺度的相互作用。更广泛地说，这些尺度相互作用的描述正是LES计算中可行子网格模型开发所需的信息。HFR-PIV系统独特地提供了这种能力。目前将直接受益于HFR-PIV系统的研究活动有：-水翼和涡轮叶片的空化动力学研究；控制部分空化流的第一步-湍流边界层动力学机制的尺度分离效应-聚合物喷射分离流控制湍流产生的噪声的实验研究-可行的流内潮汐能海洋涡轮机设计的开发和测试-更广泛的影响大约8名博士、12名硕士和一些本科生的论文研究和研究教育将在这项资助的三年内直接受到该仪器的影响。该仪器将用于新开设的研究生实验课程。此外，从研究活动中自然产生的时间分辨定量流动可视化影片将用于本科流体力学教育。有一个实验工具，可以激发学生探索流体现象的复杂性，将更容易吸引各种背景的学生来学习这门学科。将HFR-PIV系统纳入上述活动也可能产生许多更广泛的社会影响。例如，高雷诺数边界层的研究成果，在许多自然过程和技术上重要的流动中无处不在。同样，这一仪器将大大提高我们探索流体动力学现象的能力，这对发展与替代能源有关的技术很重要。这种能力直接支持更广泛的、学院范围的计划。

CBET-0821608WosnikThis MRI project funds for the acquisition of an integrated High Frame-Rate Particle Image Velocimetry (HFR-PIV) system, to obtain highresolution, time-resolved, whole-field, quantitative experimental data in a variety of turbulent flows. Time-resolved whole-field flow measurements - inaccessible prior to the development of HFR-PIV systems - have the potential to greatly advance our understanding of flow physics, and will play an important role in the creation of advanced simulation tools, for example the parametrization of subgrid-scale processes for large eddy simulations. HFR-PIV will also be a key measurement technique to be used in the NSF EPSCoR-funded large scale facility for the development and testing of sensing, prediction, actuation and control technologies in high Reynolds number turbulent boundary layer flows (Klewicki et al. 2006). The instrumentation will be used by the principle investigators and their research groups, other UNH researchers working in experimental fluid dynamics, as well as students in new graduate experimental courses. Intellectual Merit: The instrument allows spatial structure to be understood in the context of its temporal evolution. This capability is a primary obstacle preventing our understanding of complex fluid phenomena. For example, high frame-rate PIV of both the liquid and gas phases in cavitating flows will, for the first time, provide a bridge between the large body of qualitative work (high speed photography, videos) and quantitative flow measurement. In turbulent boundary layers, advancing the current state of knowledge of the transport mechanisms requires flow field information that captures the interactions across spatial scales of the dynamical motions as these motions evolve in time. More broadly, a description of these scale interactions is precisely the information required in the development of viable subgrid models in LES computations. The HFR-PIV system uniquely provides this capability. Current research activities that will benefit directly from the HFR-PIV system are:- Investigation of cavitation dynamics on hydrofoils and turbine blades, a first step towards control of partially cavitating flows- Scale separation effects on the dynamical mechanisms of turbulent boundary layers- Experimental Studies of Separated Flows with Polymer Ejection for Control of Turbulence Generated Noise- Development and Testing of Viable Ocean Turbine Designs for In-Stream Tidal EnergyBroader Impact: The thesis research and research education of approximately 8 Ph.D, 12 M.S. and a number of undergraduate students will be directly affected by the availability of this instrument through the three years of this grant. The instrument will be used in newly created experimental graduate courses. Additionally, the time-resolved quantitative flow visualization movies that come naturally from research activities will be used in undergraduate fluid mechanics education. Having an experimental tool that can inspire students to explore the complexity of fluid phenomena will make it easier to attract students of all backgrounds to this subject. Many broader societal impacts may also result from the integration of the HFR-PIV system into the described activities. For example, the outcomes from the research on high Reynolds number boundary layers, which are omnipresent in many natural processes and technologically important flows. Similarly, this instrument will substantively increase our capacity to explore fluid dynamical phenomena important to the development of alternative energy related technologies. This capability directly supports broader, College-wide, initiatives.