Upgrade of a Two Axis, Foward-Scatter, Laser-Doppler Velocimeter used in Flume Studies of Oceanographic Processes

伍兹霍尔海洋研究所的海岸研究实验室将升级老化的两轴前向散射激光多普勒体积计(LDV)。LDV安装在一个17米长的大型循环海水水槽上，供大量调查人员用于各种项目。由于盐雾的持续存在，该系统的几个电子和光电部件随着时间的推移而恶化，其他部件已经过时。该水槽提供了稳定的循环海水流动，并在水槽内建立了实验，以测量与实验相关的细尺度流动特性和湍流脉动。激光多普勒测速仪测量的是两束对准气流的激光产生的多普勒频移。先进的信号处理被用来得出流动的海水的详细模式。利用水槽和LDV来更好地了解流动特性，对于研究海洋过程，特别是在底部边界层内，正变得越来越重要。这一升级将具有成本效益地提供可供共享使用的最先进的系统。

The Coastal Research Laboratory at the Woods Hole Oceanographic Institution will upgrade an aging two-axis, forward-scatter laser Doppler volicimeter (LDV). The LDV is mounted on a large 17-meter recirculating seawater flume that is used by a large number of investigators for a variety of projects. Several electronic and electro-optical components of the system have deteriorated over time due to the continual presence of salt aerosols and others have become obsolete. The flume provides a steady flow of recirculating seawater and experiments are set up in the flume to measure the fine-scale flow characteristics and turbulence fluctuations assoc- iated with the experiment. The LDV measures the Doppler frequency shift from two laser beams that are aimed into the flow. Advanced signal processing is used to derive detailed patterns of the flowing seawater. The use of flumes and LDVs for better under- standing flow characteristics is becoming increasingly important for studying oceanographic processes, especially within the bottom boundary layer. This upgrade will cost-effectively provide a state-of-the-art system that will be available for shared use.