Direct Measurements of Dissipation Rate and Determination of the Velocity/pressure-gradient Correlation in Complex High Reynolds Number Turbulent Flows

建议没有。项目类型：研究者发起主要研究者：ROGER L. simpson机构：弗吉尼亚理工学院复杂湍流耗散率和相关性的直接测量显然需要大大改进实际三维高雷诺数湍流的湍流模型，以促进强大和准确的计算工具的发展。这些改进将对所有流体机械的设计计算产生重大影响，包括飞机、潜艇、喷气发动机等，以及对大气和海洋流动的预测。在许多模型中使用的控制雷诺平均方程中的一些项从未被直接测量过，其潜在的理论思想是高度不确定的。这个项目将提供一个重大的实验突破。一种新设计的激光多普勒测速仪正在使用和进一步开发，它可以立即确定200微米测量体积内跟随流动的多个粒子的位置，速度和加速度的三个组成部分。不仅可以确定粒子的瞬时位置在1微米（0.00004英寸）以内的不确定性，而且可以获得瞬时变化率和流动角速度，从而确定基本方程中重要项的瞬时值。这些信息对改进湍流模型非常重要。该实验技术将用于获取三种基本构造块流的数据：二维平板零平均压力梯度边界层（动量厚度雷诺数在7000 ~ 23000之间）、二维孤立粗糙度湍流边界层和三维粗糙壁边界层。这项研究的实验结果将是第一个完整测量雷诺平均模型方程中相对高雷诺数下所有湍流量的可用数据集。这项研究将产生许多广泛的影响。计划与湍流建模者进行重要的互动和合作，这将广泛传播结果，以增强科学和技术理解。其他广泛的影响包括美国本科生和研究生在使用这一尖端研究技术方面的教育，通过开发新仪器对研究基础设施的重大贡献，以及通过实际应用湍流建模的进步对社会的好处。

PROPOSAL NO.: CTS-0233653PROPOSAL TYPE: INVESTIGATOR INITIATEDPRINCIPAL INVESTIGATORS: ROGER L. SIMPSONINSTITUTION: VIRGINIA POLYTECHNIC INST. DIRECT MEASUREMENTS OF DISSIPATION RATE AND CORRELATIONS IN COMPLEX TURBULENT FLOWSThere is a clear need to greatly improve turbulent flow models for practical three-dimensional high Reynolds number turbulent flows in order to facilitate development of robust and accurate computational tools. Improvements will have a great impact on the design calculations of all fluid machinery, including aircraft, submarines, jet engines, etc. as well as the prediction of atmospheric and ocean flows. Some terms in the governing Reynolds-averaged equations used in many models have never been directly measured and the underlying theoretical ideas are highly uncertain.This program will provide a major experimental breakthrough. A newly designed type of laser-Doppler velocimeter is being used and further developed that can determine instantaneously the three components of position, velocity, and acceleration of multiple particles that follow the flow within a 200 micron measurement volume. Not only will the instantaneous position of the particles be determined to within 1 micron (0.00004 inches) uncertainty, but the instantaneous rate-of-deformation and angular velocity of the flow will be obtained, leading to the determination of the instantaneous values of important terms in the fundamental equations. The information is important for improved turbulence modeling. The experimental technique will be used to obtain data for three fundamental building block flows: 2-D flat plate zero mean pressure gradient boundary layers (momentum thickness Reynolds number in the range 7,000 to 23,000), two-dimensional turbulent boundary layers with isolated roughness, and three-dimensional rough-wall boundary layers. The experimental results from this proposed research will be the first available data sets with complete measurements of all turbulent quantities in the Reynolds-averaged modeling equations at relatively high Reynolds numbers. This research will have a number of broad impacts. Significant interaction and collaboration with turbulence modelers is planned, which will broadly disseminate the results for enhanced scientific and technical understanding. Other broad impacts are the education of US undergraduate and graduate students in the use of this cutting-edge research technique, significant contributions to research infrastructure by developing a new instrument, and benefits to society through advancements in turbulence modeling for practical applications.