Development of turbulence downstream of submerged aquatic vegetation
Abstract/Contents
- Abstract
- Seagrasses modify the flow going through them by imparting drag on the flow, leading to significant mean shear at the canopy height. The lingering effects of the canopy have profound implications for propagule transport and sediment transport downstream. My results show the presence of four distinct downstream regions in unidirectional flows. These four regions are 1) the mixing layer region, 2) the transition region, 3) the decaying turbulence region, and 4) the boundary layer region. Through these regions, the velocity straightens from a mixing-layer profile towards a boundary layer profile, but the turbulence kinetic energy (TKE) takes a non-monotonic path. The remnant effects of the TKE generated by the canopy linger for up to thirty canopy heights downstream. In wave-current flows, a mean downward velocity emerges in the lee of the canopy. This downward velocity moderates the downward transport of TKE towards the bed. For larger waves, a phase-dependence of TKE emerges and mean recirculation is found. When the findings are implemented into a fruit transport model, the dispersal kernels of the fruit seem to collapse with the free-stream velocity, release height, and particle radius. In unidirectional flows, light particles are most sensitive to vertical turbulent fluctuations, while heavy particles are more sensitive to fluctuations in the horizontal velocity. For waves, the same holds true, but because of the mean vertical velocity, the fruit is not advected as far as the fruit in the unidirectional case.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2017 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Zarama, Francisco J. M |
|---|---|
| Associated with | Stanford University, Civil & Environmental Engineering Department. |
| Primary advisor | Koseff, Jeffrey Russell |
| Thesis advisor | Koseff, Jeffrey Russell |
| Thesis advisor | Fringer, Oliver B. (Oliver Bartlett) |
| Thesis advisor | Monismith, Stephen Gene |
| Thesis advisor | Ouellette, Nicholas (Nicholas Testroet), 1980- |
| Advisor | Fringer, Oliver B. (Oliver Bartlett) |
| Advisor | Monismith, Stephen Gene |
| Advisor | Ouellette, Nicholas (Nicholas Testroet), 1980- |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Francisco J. M. Zarama. |
|---|---|
| Note | Submitted to the Department of Civil and Environmental Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2017. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2017 by Francisco Jose Maria Zarama
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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