Particle Tracking in High Reynolds Number Turbulent Flows

本研究计划进一步发展高能物理探测器的硅条技术，用于三维粒子跟踪。关于湍流的拉格朗日性质的基本问题没有答案，我们测试理论模型的能力非常有限。尚未解决的重要问题包括流体粒子加速度的统计、拉格朗日结构函数的惯性范围缩放和n粒子湍流色散。这项新技术允许在足够的空间和时间分辨率下在三维中跟踪四个粒子，为测量高雷诺数湍流耗散和内部范围内的单个和多个粒子朗日统计提供了设施。同时，在无平均速度的流动中产生高雷诺数的各向同性均匀湍流的新方法也得到了发展。这些测量将提供与理论预测比较所需的数据，并可能引发理论研究的新方向。此外，它们将提供解决从湍流燃烧到大气中污染物输送等许多过程中的湍流扩散问题所需的重要信息。它还保证了高速条带探测器作为一种通用工具的持续发展，它可以用于许多需要实时跟踪弱光条纹的测量。

In this research program the silicon strip technology from High Energy Physics detectors is further developed for three dimensional particle tracking. Fundamental questions about Lagrangian properties of turbulence are unanswered, and our ability to test theoretical models is very limited. Important unsolved problems include statistics of the fluid particle acceleration, inertial range scaling of the Lagrangian structure functions, and n-particle turbulent dispersion. This new technology allows to follow up to four particles in three dimensions at sufficient spatial and temporal resolution to provide the facility to measure single and multiple particle Langrangian statistics in the dissipation and interial range of high Reynolds number turbulence. Simultaneously, new ways are developed to generate very high Reynolds number isotropic and homogeneous turbulence in flows with no mean velocity. These measurements will provide much needed data to compare with theoretical predictions and may trigger new directions in theoretical research. In addition, they will give important information needed to address problems of turbulent diffusion in many processes ranging from turbulent combustion to pollutant transport in the atmosphere. It also promises the continued development of high speed strip detectors as a general purpose tool which can be used for many measurements where a weak light streak has to be followed in real time.