碩士 / 中原大學 / 土木工程研究所 / 100 / In this research, a numerical scheme that employs a generalizedvortex method is used to simulate the
two-dimensional flow around acircular cylinder placed at various heights above a plane boundary andexposed to a solitary wave. The vortical flow field is solved via a vortex method, the irrotational flow field and the motion of the free surface aresolved using a boundary integral technique.
In order to understand the hydrodynamic force exerted on the submarine pipeline under wave action, a series of simulations were performed with various gap-to-diameter ratios and wave heights to study their effects on vortex
generation as well as the drag exerted on the cylinder.
According to the numerical results, changes in
gap-to-diameter ratios have a significant impact on the evolution of the hydrodynamicforce and vortices. As the value of gap-to-diameter ratio increases, the drag force exerted by the circular cylinder decreases. When the value
of the gap-to-diameter ratio is greater than 1.5, the gap height is large enough so that there is no interplay between the separating shear layers generated from the cylinder and from the seabed; there force, the variation
of the drag and to the gap height is insignificant. When the solitary wave crest is passing through the cylinder, strong shear stress is generated on the seabed, and is
not affected by the gap ratio. As the wave height increases, seabed shear stress is more and more strong. At the gap ratio is the 0.25 and 0.5, in the gap between the cylinder
and the flat bottom, positive and negative vorticity appear at the same time. This condition may have significant influence on seabed erosion and sediment transport.
| Identifer | oai:union.ndltd.org:TW/100CYCU5015032 |
| Date | January 2012 |
| Creators | Guo-Jhen Liao, 廖國禎 |
| Contributors | Meng-Yu Lin, 林孟郁 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 133 |
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