碩士 / 國立成功大學 / 水利及海洋工程學系 / 84 / Water waves incident on a sandy beach may generate nearshore
circulations behinddetach breakwaters, which produce a varying
sediment transport field resultingin shoreline changes. Previous
one-line models with no flow field are limitedto describe
shoreline response to detached breakwaters. A numerical
modelincludes three submodels predicting wave field, nearshore
currents and shorelinechanges behind a single permeable
breakwater is developed in this paper. The mild-slope equation
with a combination of refraction diffraction andreflection is
solved in the form of hyperbolic approximation. Wave-
inducednearshore currents are calculated on the basis of
radiation stresses obtainedfrom wave field. Shoreline changes
behind a single parallel detached breakwateris predicted from
nearshore currents and continuity of sediment transport.
Thevalidity of the present model is verified through experiments
and reasonableagreements are found. The effects of wave
steepness, distance from the shoreline to the breakwaterand
porosity on shoreline changes are investigated. Numerical
results showthat the ability of a breakwater to shelter water
bodies from waves and formsand salient and tombolos decreased
with the increase of the porosily. Thesalient grows and advances
as the wave height and wave period increases.Sand spits don''t
protrude in the case of S/B=1.25 , where S is the
offshoredistance and B is the length of the detached breakwater,
respectively.
| Identifer | oai:union.ndltd.org:TW/084NCKU0083006 |
| Date | January 1996 |
| Creators | Shu, Li Zen, 徐立政 |
| Contributors | Hsu Tai Wen, 許泰文 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 77 |
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