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

建议没有。： cbet - 0730774首席研究员：simpson， Roger l.表面驱动液体流动的纳米流体学及其在纳米制造中的应用在本研究项目中，新的综合激光多普勒测速仪（CompLDV）实验技术将同时精确地测量瞬时矢量速度、加速度、以每秒至少100,000个样本的高数据速率，在高雷诺数三维湍流的Kolmogorov尺度内，亚微米大小的颗粒的位置。CompLDV的新设计叠加了会聚和发散条纹图案，在5微米的不确定度内确定给定粒子通过200微米直径的测量体积的三维位置。测量可以在固体壁的5微米范围内进行，以确定表面皮肤摩擦。对于三维流动，这些输运方程需要考虑：(1)涡流粘度的可变各向异性，(2)平均流与湍流场之间的滞后，以及(3)重要剪应力与速度波动之间的密切关系（Simpson, 1996）。这里计划的工作将为机翼/机身测试流和涡发生器流检查马蹄形涡结构，以提供定量数据，以更好地解释和模拟实际应用中常见的嵌入式平均流向涡的三维湍流结构。此外，在本研究中需要关于流动的全局非定常和不同大小涡流长度尺度的实验统计信息，并将使用多点LDV测量获得这些数据和结果，以与大涡流模拟（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。这项计划研究的更广泛影响是，通过继续开发一种新型仪器，可以首次提供关于湍流能量耗散率、速度/压力梯度相关性和其他先前未测量的定义良好的高雷诺数三维湍流边界层的基本低不确定性信息，从而促进发现和理解，并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。计划中的研究生也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有望参与这些结果的讨论。从规划的三维流动中获得的知识和见解将使速度/压力梯度相关性和高雷诺数耗散率的模型更加可信，这对于天气预报和更好地估计湍流产生的气动声学噪声源是必要的。

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.