Micro-Scale Turbulence Measurements Using a Nano-Scale Thermal Anemometry Probe (NSTAP)

建议编号：CTS-0625268 PRINCIPAL调查员：Alexander SMITSINSTUTION：普林斯顿大学使用纳米尺度热风速探头(NSTAP)进行微尺度湍流测量这笔赠款将有助于使用PI开发的一种新仪器研究高雷诺数流动中的小尺度湍流。高雷诺数的湍流是许多工业应用的特征，包括用于输送石油和天然气、飞机、船舶和潜艇的管流。由于缺乏适当的实验设施和缺乏适当的表征技术，这些极端制度历来是无法进入的。然而，将最先进的设施与普林斯顿大学最近开发的纳米级热风速探测器(NSTAP)相结合，为研究这些重要的技术流动打开了机会。研究集中在三个尚未解决的问题上：湍流强度相似公式的分析和发展，谱标度区域的分析和发展，以及Kolmogorov湍流理论的验证。普林斯顿大学开发的SuperPIPE和HRTF设备使高雷诺数湍流的研究成为可能，但目前可用的仪器的空间分辨率不足以研究流动中存在的所有尺度。由于NSTAP的成功开发，研究小尺度(1-10微米)湍流的能力现在成为可能。该探头由一根使用标准纳米制造技术制造的铂纳米线组成。探头的继续发展，推动了更小的尺寸，目的是生产和表征一种金属丝(10-50纳米宽x 1-10微米长)。这种传感导线将具有在空间和时间尺度上测量流体流动的独特能力，比目前用现有仪器所能研究的小两个数量级。这项工作的成功将对流体力学的研究人员产生广泛的影响，从而提高对湍流的理解。开发NSTAP的方法还将为更深入地理解自由金属纳米线的形成和反应所依据的材料科学和物理学打开大门。例如，这项研究将产生关于金属纳米线的机械和电子性能的知识，这些知识可能会用于其他应用，如芯片内互连。由于制造技术和导线中的电流流动而发生的电迁移、再结晶和本征应力演变等影响对其他领域的研究人员很重要，并将在本研究过程中进行研究。这个项目将极大地受益于流体力学和材料科学的学生和教师研究人员之间的密切合作，使这两种类型的专家能够了解对方的领域。为这些研究实施的NSTAP将通过纳米制造和湍流测量的实践来教育学生。本研究将通过学期项目和暑期研究经验方便本科生参与。

PROPOSAL NO.: CTS-0625268PRINCIPAL INVESTIGATOR: ALEXANDER SMITSINSTITUTION: PRINCETON UNIVERSITYMicro-Scale Turbulence Measurements Using a Nano-Scale Thermal Anemometry Probe (NSTAP)This grant will facilitate study of turbulence at small length scales in high Reynolds number flows using a novel instrument developed by the PI. Turbulence at high Reynolds numbers is characteristic of many industrial applications, including pipe flows for transporting oil and gas, aircraft, ships and submarines. These extreme regimes have historically been inaccessible due to the paucity of appropriate experimental facilities and the lack of suitable characterization techniques. However, the combination of state-of-the-art facilities with the recent development of a nanoscale thermal anemometry probe (NSTAP) at Princeton, opens up the opportunity to study these technologically important flows. The research focuses on three unresolved topics in fluid mechanics; the analysis and development of turbulence intensity similarity formulations, the analysis and development of the spectral scaling regions, and the verification of the Kolmogorov turbulence theories. The Superpipe and HRTF facilities developed at Princeton make possible the study of high Reynolds number turbulence, but the spatial resolution of currently available instrumentation is inadequate to study the full range of scales present in the flow. The ability to study turbulence on the small (1-10 micron) size scale is now made possible by the successful development of the NSTAP. The probe consists of a platinum nanowire fabricated using standard nanofabrication techniques. Continued development of the probe, pushes toward even smaller sizes, with the aim of producing and characterizing a wire (10 - 50 nm wide x 1-10 microns long). Such a sensing wire will have the unique capability of measuring fluid flow on spatial and temporal scales two orders of magnitude smaller than can currently be studied with existing instrumentation. The success of this work will have broad implications for researchers in fluid mechanics, leading to an improved understanding of turbulent flows. The approaches in developing NSTAP will also open the door to a deeper understanding of the materials science and physics underlying the formation and response of a free standing metallic nanowire. For instance, this study will generate knowledge on the mechanical and electronic properties metallic nanowires, which may be used in other applications such as on-chip interconnects. Effects such as electromigration, recrystallization, and intrinsic stress evolution that occur due to fabrication techniques and current flow in the wire are important to researchers in other areas and will be examined over the course of this study. This project will greatly benefit from close collaborations among a diverse blend of student and faculty researchers in fluid mechanics and materials science enabling both types of specialists to learn about the other's field. The implementation of the NSTAP for these studies will educate students through the practices of both nanofabrication and turbulence measurements. The research will be readily accessible for undergraduate participation through term projects and summer research experience.