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

提案编号：CTS-0625268主要研究者：亚历山大·史密斯研究机构：普林斯顿大学使用纳米尺度热风速计探针（NSTAP）进行微尺度湍流测量该资助将促进使用PI开发的新型仪器在高雷诺数流动中进行小长度尺度湍流研究。高雷诺数下的湍流是许多工业应用的特征，包括用于运输石油和天然气的管流、飞机、船舶和潜艇。由于缺乏适当的实验设施和适当的表征技术，这些极端的制度历来是无法接近的。然而，结合国家的最先进的设施与最近开发的纳米热风速仪探头（NSTAP）在普林斯顿大学，开辟了机会，研究这些技术上重要的流量。研究重点是流体力学中三个尚未解决的问题;湍流强度相似性公式的分析和发展，光谱标度区域的分析和发展，以及Kolmogorov湍流理论的验证。 在普林斯顿大学开发的Superpipe和HRTF设备使得高雷诺数湍流的研究成为可能，但是目前可用的仪器的空间分辨率不足以研究流动中存在的全部尺度。由于NSTAP的成功发展，现在有可能在小尺度（1-10微米）上研究湍流。 探针由使用标准纳米纤维技术制造的铂纳米线组成。探针的持续发展，推动了更小的尺寸，目的是生产和表征导线（10 - 50 nm宽x 1-10微米长）。 这种传感线将具有独特的能力，测量流体流量的空间和时间尺度上的两个数量级小于目前可以研究与现有的仪器。 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的方法也将为更深入地理解独立金属纳米线的形成和响应背后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特性的知识，这些知识可以用于其他应用，如芯片上的互连。 影响，如电迁移，再结晶，和内在应力的演变，发生由于制造技术和电流在电线是重要的研究人员在其他领域，并将在本研究的过程中进行检查。该项目将极大地受益于流体力学和材料科学领域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。NSTAP在这些研究中的实施将通过纳米纤维和湍流测量的实践来教育学生。该研究将通过学期项目和夏季研究经验随时为本科生参与。

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.