Time Dependent Particle Image Velocimetry (PIV) Measurement via Linear Stochastic Estimation (LSE)

目前，由于脉冲YAG激光器的带宽限制（通常为15 Hz或更低），粒子图像测速（PIV）测量无法在足够高的采样率下通过实验获得。这在处理高雷诺数流动时，特别是处理时间依赖和时间演化的流动时，如果需要的不仅仅是流动的快照，就会产生问题。本研究的目的是开发和微调一种基于二维（2-D）空间线性随机估计（LSE）的技术，这将为低样本率问题提供解决方案。该方法将热线优越的时间带宽特性与PIV优越的空间分辨率相结合。瞬时速度通过热线测速法在空间中几个最佳选择的点进行测量，然后在已知从PIV测量获得的相关性的剩余空间位置估计同步速度。这项重要的新技术可以在克拉克森大学发挥其最大的潜力。此外，PIV系统将为实验湍流实验室增加急需的能力，并将影响几个当前和未来的主要实验研究项目。

Abstract CTS-9809784 Glauser & Ahmadi Clarkson University Presently Particle Image Velocimetry (PIV) measurement cannot be experimentally obtained at sufficiently high sample rates due to bandwidth limitation with pulsed YAG lasers (15 Hz or less typically). This poses a problem when dealing with high Reynolds number flows and, in particular, with time dependent and temporally evolving flows if more than just snapshots of the flow are required. The objective of this research is to develop and fine tune a technique that is based on two-dimensional (2-D) Spatial Linear Stochastic Estimation (LSE) which will provide a solution to the low sample rate problem. The method combines the outstanding temporal bandwidth characteristics of hot-wires with the superb spatial resolution of the PIV. The instantaneous velocities are measured via hot-wire anemometry at a few optimally selected points in space, simultaneous velocities are then estimated at the remaining spatial positions where the correlations, obtained from the PIV measurements, are known. This new and important technique can be developed to its fullest potential at Clarkson University. In addition, the PIV system will add a much needed capability to the Experimental Turbulence Laboratory and will impact several current and future major experimental research projects.