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Hydrodynamics of mangrove root-type models
| Title: | Hydrodynamics of mangrove root-type models. |
 649 views 540 downloads |
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| Name(s): |
Kazemi, Amirkhosro, author Curet, Oscar M., Thesis advisor Florida Atlantic University, Degree grantor College of Engineering and Computer Science Department of Ocean and Mechanical Engineering |
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| Type of Resource: | text | |
| Genre: | Electronic Thesis Or Dissertation | |
| Date Created: | 2017 | |
| Date Issued: | 2017 | |
| Publisher: | Florida Atlantic University | |
| Place of Publication: | Boca Raton, Fla. | |
| Physical Form: | application/pdf | |
| Extent: | 101 p. | |
| Language(s): | English | |
| Summary: | Mangrove trees play a prominent role in coastal tropic and subtropical regions, providing habitat for many organisms and protecting shorelines against storm surges, high winds, erosion, and tsunamis. The motivation of this proposal is to understand the complex interaction of mangrove roots during tidal flow conditions using simplified physical models. In this dissertation, the mangrove roots were modeled with a circular array of cylinders with different porosities and spacing ratios. In addition, we modeled the flexibility of the roots by attaching rigid cylinders to hinge connectors. The models were tested in a water tunnel for a range of Reynolds number from 2200 to 11000. Additionally, we performed 2D flow visualization for different root models in a flowing soap film setup. We measured drag force and the instantanous streamwise velocity downstream of the models. Furthermore, we investigated the fluid dynamics downstream of the models using a 2-D time-resolved particle image velocimetry (PIV), and flow visualization. The result was analyzed to present time-averaged and time-resolved flow parameters including the velocity distribution, vorticity, streamline, Reynolds shear stress and turbulent kinetic energy. We found that the frequency of the vortex shedding increases as the diameter of the small cylinders decreases while the patch diameter is constant, therefore increasing the Strouhal number, St=fD/U By comparing the change of Strouhal numbers with a single solid cylinder, we introduced a new length scale, the “effective diameter”. In addition, the effective diameter of the patch decreases as the porosity increases. In addition, patch drag decreases linearly as the spacing ratio increases. For flexible cylinders, we found that a decrease in stiffness increases both patch drag and the wake deficit behind the patch in a similar fashion as increasing the blockage of the patch. The average drag coefficient decreased with increasing Reynolds number and with increasing porosity. We found that the Reynolds stress (−u′v′) peak is not only shifted in the vortex structure because of shear layer interference, but also the intensity was weakened by increasing the porosity, which causes a weakening of the buckling of vorticity layers leading to a decline in vortex strength as well as increase in wake elongation. | |
| Identifier: | FA00004948 (IID) | |
| Degree granted: | Dissertation (Ph.D.)--Florida Atlantic University, 2017. | |
| Collection: | FAU Electronic Theses and Dissertations Collection | |
| Note(s): | Includes bibliography. | |
| Subject(s): |
Fluid mechanics. Atmospheric models. Ocean currents--Mathematical models. Sediment transport. Estuarine oceanography. |
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| Held by: | Florida Atlantic University Libraries | |
| Sublocation: | Digital Library | |
| Links: | http://purl.flvc.org/fau/fd/FA00004948 | |
| Persistent Link to This Record: | http://purl.flvc.org/fau/fd/FA00004948 | |
| Use and Reproduction: | Copyright © is held by the author, with permission granted to Florida Atlantic University to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder. | |
| Use and Reproduction: | http://rightsstatements.org/vocab/InC/1.0/ | |
| Host Institution: | FAU | |
| Is Part of Series: | Florida Atlantic University Digital Library Collections. |
