Design and validation of an in situ 3D PTV system for ocean turbulence
- Small-scale mixing in the ocean has large scale implications for the global ocean circulation, heat budget, and climate system. Physically based parameterizations are necessary to represent these unresolved processes in global ocean models. Efforts to characterize stratified turbulence have been limited by the ability to measure the full time-resolved, small-scale, 3D velocity field. Existing instrumentation, such as shear probes and acoustic doppler current meters, measure velocities or velocity gradients at a single point or in a profile, and thus require invoking assumptions such as isotropy and Taylor's frozen turbulence to estimates of dissipation. Here, we develop a novel instrument to perform in situ 3D particle tracking velocimetry (PTV) to measure the full 3D velocity field, so that quantities like dissipation can be estimated with minimal assumptions. First, this dissertation discusses the conceptual design of the 3D PTV system, specifically the measurement criteria for ocean turbulence and the considerations required to configure a traditionally laboratory technique into a field deployable instrument. Next, the hardware build of the 3D PTV system is detailed, as well as initial validation. Laboratory and field validation was conducted, and demonstrated that the 3D PTV system can measure mean flows, waves, turbulent fluctuations based on comparison with an ADV. The 3D PTV system was able to measure particle tracks within a 20cm^3 volume, and second order Eulerian structure functions could be calculated. The structure function followed the r^(2/3) inertial range scaling between 100-160mm, and this result was consistent for different sequences and different averaging intervals. The findings validate a proof-of-concept for the use of 3D PTV for studying ocean mixing.
|Type of resource
|electronic resource; remote; computer; online resource
|1 online resource.
|Yin, Jennifer Zhang
|Degree committee member
|Degree committee member
|Stanford University, School of Engineering
|Stanford University, Civil & Environmental Engineering Department
|Statement of responsibility
|Jennifer Zhang Yin.
|Submitted to the Civil & Environmental Engineering Department.
|Thesis Ph.D. Stanford University 2023.
- © 2023 by Jennifer Zhang Yin
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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