Research on the Structure of Complex 3-D Turbulent Flows Using the Comprehensive Laser-Doppler Velocimeter

提案编号：CBET - 0730774主要制造商：SIMPSON，ROGER L. 机构：弗吉尼亚理工大学和州立大学表面驱动液体流动的纳米流体及其在纳米制造中的应用在这项研究计划中，新的综合激光多普勒测速仪（CompLDV）实验技术将同时精确测量瞬时矢量速度，加速度，和亚微米尺寸颗粒在高雷诺数3-D湍流的Kolmogorov尺度内的位置，000个样本每秒。CompLDV新设计叠加会聚和发散条纹图案，以确定通过200微米直径测量体积的给定颗粒的3-D位置，误差在5微米内。可以在固体壁的5微米内进行测量，以确定表面摩擦力。对于三维流动，需要这些输运方程来解释：（1）涡流粘度的各向异性，（2）平均流和湍流场之间的滞后，（3）重要的剪切应力和速度波动之间的强关系（Simpson，1996）。这里计划的工作将检查这个机翼/机身试验情况流和涡流发生器流的马蹄形涡流结构，以提供定量数据，更好地解释和模拟实际应用中常见的嵌入平均流向涡流的三维紊流结构。此外，在本研究中，需要关于流动的全局不稳定性和各种尺寸的涡的长度尺度的实验统计信息，并将使用多点LDV测量来获得这些数据和结果，以与大涡模拟（LES）进行比较，这些数据和结果将与欧洲流体、湍流和燃烧研究共同体（ERCOFTAC）和其他合作者共享。这一计划中的研究的更广泛的影响，推进发现和理解，并通过继续开发一种新型的仪器，可以提供基本的低不确定性信息的湍流能量耗散率和速度/压力梯度的相关性和其他以前未测量的量明确定义的高雷诺数三维湍流边界层，增强湍流研究的基础设施。PI和湍流建模者之间的合作已经建立。计划中的研究生将与这些研究人员互动，帮助从数据中开发湍流模型。来自德国的研究生和其他建模研究人员预计将参与这些结果的讨论。从计划的三维流动中获得的知识和见解将允许在高雷诺数下建立更可靠的速度/压力梯度相关性和耗散率模型，这是天气预报和更好地估计湍流产生的航空声学噪声源所需的。

PROPOSAL NO.: CBET - 0730774 PRINCIPAL INVESTIGATOR: SIMPSON, ROGER L. INSTITUTION: VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITYNANOFLUIDICS OF SURFACE-DRIVEN LIQUID FLOW AND ITS APPLICATION FOR NANOFABRICATIONIn this research program, the new comprehensive laser-Doppler velocimeter (CompLDV) experimental technique will measure simultaneously and precisely the instantaneous vector velocity, acceleration, and position of submicron-sized particles within the Kolmogorov scales of high Reynolds number 3-D turbulent flows at a high data rate of at least 100,000 samples per second. The CompLDV novel design superimposes converging and diverging fringe patterns to determine the 3-D location of a given particle passing through the 200 micron diameter measurement volume within 5 microns uncertainty. Measurements can be made within 5 microns of a solid wall to determine the surface skin friction. For 3-D flows, these transport equations are required to account for: (1) the variable anisotropy of the eddy viscosities, (2) the lags between the mean flow and the turbulence field, and (3) the strong relation between the important shearing stresses and velocity fluctuations (Simpson, 1996). Work planned here will examine the horseshoe vortex structure for this wing/body test case flow and for a vortex generator flow to provide quantitative data to better explain and model the 3-D turbulence structure of embedded mean stream-wise vortices common in practical applications. In addition, in this research experimental statistical information on the global unsteadiness of the flow and the length scales of the various sized eddies are needed and will be obtained using multi-point LDV measurements to compare with large-eddy simulations (LES), These data and results will be shared with European Research Community on Fluids, Turbulence and Combustion (ERCOFTAC) and other collaborators. The broader impacts of this planned research advances discovery and understanding and enhances the infrastructure of turbulence research by continuing to develop a new type of instrument that can provide fundamental low uncertainty information for the first time on the turbulence energy dissipation rate and the velocity/pressure-gradient correlation and other previously unmeasured quantities for well-defined high Reynolds number three-dimensional turbulent boundary layers. Collaborations between the PI and turbulence modelers have already been established. The planned graduate student will interact with these researchers also in helping to develop turbulence models from the data. Graduate students from Germany and other modeling researchers are expected to be involved in the discussions of these results. The knowledge and insights gained from the planned three-dimensional flows will permit more credible models for the velocity/pressure-gradient correlation and dissipation rate at high Reynolds numbers, which are needed for weather prediction and better estimates of the turbulence generated aero-acoustic noise sources.