SBIR Phase I: A Fiber-Optic, Simultaneous, Multi-Point Turbulent Kinetic Energy Rate Dissipation Sensor

本小型企业创新研究第一阶段项目提出了一种用于测量海上和实验室湍流动能耗散率的激光装置。该传感器在许多海洋学/流体动力学应用中很有价值。例如，由于耗散率通常与摩擦速度的三次幂有关，因此它是海底和海面边界层中最敏感的动力学测量；它对海洋内部的观测同样至关重要，因为海洋内部的混合具有强烈的基础兴趣，并且对通过有机和地球化学颗粒运输研究碳循环具有应用兴趣。新的传感器概念是基于对短时间段的无偏，直接估计加速度方差，然后使用泰勒假设对每个段转换为空间梯度。该激光装置不仅能够在提供耗散欧拉测量的固定平台上运行，而且还适用于比现有传感器测量的耗散率高得多的情况。最后，这里提出的能力不仅将提供单点测量，还将是基于另一个SBIR授权正在进行的工作的同步多点传感器。由于其对欧拉测量的扩展能力、高耗散率范围和多点能力的综合能力，该技术的发展将对海洋/流体动力学的广泛科学领域做出重大贡献。由此产生的仪器也将有助于研究海洋聚集体的动力学，这些聚集体被假定为根据耗散微尺度而破裂。由此产生的耗散传感器对于研究海洋表面和底部边界层过程的科学家、研究生物初级生产力及其与湍流的相互作用的科学家以及研究海洋内部混合过程的科学家具有广泛的应用价值。

This Small Business Innovative Research Phase I project proposes a laser device for the measurement of the dissipation rate of turbulent kinetic energy in the sea as well as in the laboratory. The sensor would be valuable in a number of oceanographic/fluid dynamics applications. For example, since the dissipation rate scales typically with the third power of the friction velocity, it is the most sensitive measure of dynamics in the ocean bottom and surface boundary layers; it is similarly vital to observations in the ocean interior where mixing in the ocean is of strong fundamental interest as well as of applied interest in the study of carbon cycling via organic and geochemical particulate transport. The new sensor concept is based on the unbiased, direct estimation of acceleration variance for short-time segments, and subsequent conversion to spatial gradients using Taylor's hypothesis for each segment. The laser device will not only be able to operate from a fixed platform providing Eulerian measurements of dissipation, it is also suitable for much higher dissipation rates than can be measured with existing sensors. Finally, the capability proposed here will not only provide measurements at a single point, it will be a simultaneous multi-point sensor based on work in progress in another SBIR grant. Because of the combined capabilities of extension to Eulerian measurement, high range in dissipation rate and multi-point capability, the development could make significant contributions to a broad range of science in oceanography/fluid dynamics. The resulting instruments will also be useful in the study of dynamics of marine aggregates which are postulated to break apart depending on the dissipation microscales. The dissipation sensor resulting from this development will be of broad use of to scientists studying boundary layer processes on the ocean surface and bottom to other scientists studying biological primary productivity and its interaction with turbulence and to those studying mixing processes in the ocean interior.