SBIR Phase II: A Multi-Point Array Laser Doppler Velocimeter

Agrawal 9502488这个小型企业创新研究第二阶段项目旨在完成研究/商业原型的多点激光测速仪，用于实验室和海洋中的无人值守使用。在自然界中，单点的速度测量很少是足够的；当只有单点测速仪可用时，采用轮廓分析来获得关于流场结构的信息。轮廓信息总是通过机械遍历传感器‘头’来获得。这种方式不仅牺牲了同视性，导致结构数据的无序，而且还丢失了关于空间结构、相干运动和时空尺度的所有信息。在研究需要的推动下，P.I.设计了一种多点测速系统，该系统可以同时在流场中形成多个样本体。来自这些样品体积的信号分别被传送到光电探测器。然后需要多信号处理器将信号转换为同时多点速度数据，保留关于流动中固有顺序的信息，以及用于推导流体结构的时空尺度的所有信息。在第一阶段，我们已经成功地演示了该方法的原理，通过构造一个单速度分量多点速度计，正如第一阶段提案中第一次解释的那样。在第二阶段，我们将把能力扩展到两轴多点测速仪，带有方向识别光学装置和完整的多信号处理器。该仪器将在实验室和现场进行测试。

AGRAWAL 9502488 This Small Business Innovation Research Phase-II project is directed at the completion of a research/commercial prototype multi-point laser velocimeter for use in laboratories and also for use unattended in the ocean. Measurements of velocity at a single point are seldom sufficient in nature; when only single-point velocimeters are available, profiling is employed to obtain information regarding structures of a flow-field. Profile information has invariably been derived by mechanical traversing of a sensor 'head'. Not only is synopticity sacrificed in this manner, causing loss of order in structure data, but also all information on spatial structures, coherent motions, and space-time scales is lost. Driven by needs in his research, the P.I. has devised a multi-point velocimetry system which forms several sample volumes in the flow field simultaneously. Signals from these sample volumes are separately carried to photo-detectors. A multi-signal processor is then required to convert the signal to simultaneous- multi-point velocity data, retaining information on order inherent in the flow, and all information for deriving space-time scales of fluid structures. In Phase-I, we have successfully demonstrated the principle of the method by constructing a single-velocity- component multi-point velocimeter, as first explained in the Phase- I proposal. In Phase-II, we shall expand capabilities to a 2-axis multi-point velocimeter, with direction discrimination optics and a complete multi-signal processor. The instrument will be tested in the laboratory and the field.