A Multi-Point Array Laser Doppler Velocimeter

9361114 AGRAWAL我们建议开发一种多点激光测速仪，以同时和非侵入性地获得多个点的速度。我们特别感兴趣的是将该仪器应用于地表和底部边界层中的运输和交换。然而，该技术将适用于需要同时测量速度的大范围流动。创新的核心是一个完全非侵入式的光学几何结构，它在流动中形成几个样品体积，以及相应的接收光学来区分它们的图像。这种装置是观察自然流动中的结构和处理流动平稳性等问题所必需的。这种速度场的同步视图将消除速度剖面信息解释中的不确定性；例如，速度剪切和剪切应力，湍流特征尺度和粗糙度长度。该概念还消除了对机械扫描设备或剖面仪的需求，这两种设备都会产生非同时测量。描述了用这种仪器来表征底边界层中沉积物的浓度和输送速率。这个概念也有利于实验室科学家使用水槽、拖曳罐和风洞，因为多点测量提供了关于流动结构的额外信息，并提高了生产率。

9361114 AGRAWAL We are proposing to develop a multi-point laser velocimeter to obtain velocities at a number of points, simultaneously and non- intrusively. Our specific interest is to apply this instrumentation to transport and exchange in surface and bottom boundary layers However, the technique will be applicable to a wide range of flows where simultaneous velocity measurements are desirable. At the heart of the innovation is a completely non- intrusive optical geometry which forms several sample volumes in the flow, and corresponding receiving optics to distinguish their images. Such a device is needed to observe structures in natural flows and to deal with issues such as flow stationarity. This simultaneous view of the velocity field will remove uncertainty in the interpretation of velocity profile information; e.g. the velocity shear and shear stress, turbulent characteristic scales and roughness lengths. The concept also concept also removes the need for mechanical scanning devices or profilers, both of which yield non-simultaneous measurements. The use of this instrument for characterizing the concentration and transport rate of sediments in the bottom boundary layer is described. The concept is also beneficial to laboratory scientists using flumes, towing tanks, and wind tunnels, in that multi-point measurements provide additional information on flow structure and improve productivity.