Observations of Boundary Layer Dynamics in South San Francisco Bay
Abstract/Contents
- Abstract
- Estuarine sediment transport is an important process in determining the fate and transport of contaminants. While physical models exist to describe spherical non-flocculating particles in a fluid, cohesive sediments are poorly modeled from first principles. We conducted field work in South San Francisco Bay during the summer of 2018 to take detailed observations of sediment and water motion near the bed in the shallow eastern shoals. Data collected by a Nortek Vectrino Profiler provides insight into the patterns of flow in the wave-current boundary layer and nearby log layer, as well as the physical forcing behind bed behavior. I compare these profiles with accepted fitting models for flow over a canopy and with measurements taken higher in the water column by an Acoustic Doppler Profiler deployed at the same site. Velocity profiles at 64 Hz for 12 minutes every hour at a 1 mm resolution for 2 mm overlapping the bed are highly detailed in space and time relative to previous field measurements of similar variables, and permit the study of friction velocity and turbulent Reynolds stress in and above the wave-current boundary layer. Velocity profiles in the shallow shoals of South Bay are modeled by the canopy log law. Waves are a major contributor to instantaneous velocity profile deviations from the 12-minute mean profile, and cause corresponding variations in turbulence Reynolds stress and friction velocity. Phase-averaged velocity profiles and turbulence statistics are presented for different tide and wave environments to describe the results of complex wave-current interactions in the boundary layer. This work has implications for interpreting time-averaged velocity profile measurements and presents detailed measurements of parameters relevant to understanding sediment transport in an economically important estuary system.
Description
| Type of resource | text |
|---|---|
| Date created | May 2019 |
Creators/Contributors
| Author | Cowherd, Marianne |
|---|---|
| Degree granting institution | Stanford University, Department of Civil and Environmental Engineering |
| Primary advisor | Fringer, Oliver |
Subjects
| Subject | estuary |
|---|---|
| Subject | canopy flow |
| Subject | boundary layer |
| Subject | wave Reynolds stress |
| Subject | stanford university |
| Subject | civil & environmental engineering |
| Subject | cee |
| Subject | sediment transport |
| Subject | cohesive sediment |
| Subject | fluid mechanics |
| Subject | san francisco bay |
| Subject | south san francisco bay |
| Genre | Thesis |
Bibliographic information
Access conditions
- Use and reproduction
- User agrees that, where applicable, content will not be used to identify or to otherwise infringe the privacy or confidentiality rights of individuals. Content distributed via the Stanford Digital Repository may be subject to additional license and use restrictions applied by the depositor.
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Preferred citation
- Preferred Citation
- Cowherd, Marianne. (2019). Observations of Boundary Layer Dynamics in South San Francisco Bay. Stanford Digital Repository. Available at: https://purl.stanford.edu/wr832gx3390
Collection
Undergraduate Theses, School of Engineering
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- Contact
- cowherd@stanford.edu
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