Numerical Study of Wave Spectrum Transformation over Fringing Coral Reefs(2)

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簡歷

基本資料

Project title

Code/計畫編號

MOST104-2221-E032-063

Translated Name/計畫中文名

數值研究波浪於珊瑚裙礁之波譜變化(2)

Project Coordinator/計畫主持人

Shih-Feng Su

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Water Resources and Environmental Engineering Tamkang University

Website

https://www.grb.gov.tw/search/planDetail?id=11585048

Year

2015

Start date/計畫起

01-08-2015

Expected Completion/計畫迄

31-07-2015

Bugetid/研究經費

504千元

ResearchField/研究領域

環境科學

在海洋環境中，珊瑚礁是一個珍貴的天然資源，它提供空間給予多元的海洋生物棲息並緩衝波浪能量讓沙灘免於被侵蝕。珊瑚礁地形有別於平緩的沙質海岸，一般是由寬敞且水淺的粗糙礁石平台延伸至外海後急降至深水，水動力特性受到表面波浪與複雜地形交互作用影響而變得很複雜。雖然許多波譜模式能成功地描述波高與波揚在珊瑚礁的分布過程，但是低頻亞重力波之預測準確性仍然是一個挑戰，而這個低頻波浪在淺水的珊瑚礁環境是主要的波浪成分。這是因為模式在預測非線性波與波能量交互作用之機制並未完善。本計畫之目的是利用根據Boussinesq方程式之非線性波浪模式FUNWVE-TVD來研究波浪在各種珊瑚礁裙礁地形之變化過程，考慮到潮位、礁坡與底床摩擦影響，目前已利用一維水工模型試驗數據予以驗證模式結果，接著將利用模式與二維平面水工試驗比對，評估模式預測低頻亞重力波分布及波浪所引起之流場空間變化。進一步，模式將應用於實際珊瑚礁島嶼海岸，預測波浪引起之波流場空間變化。有了模式系統性地估算，珊瑚礁島嶼之海岸工程與氣候變遷對珊瑚礁海岸溢淹造成之衝擊都可以予以評估。 Coral reefs are precise natural resources in ocean environments. They provide habitats for a large number of marine species and protect shoreline from erosion by buffering wave energy. Geometric shapes of coral reefs, differing from sloping sandy beaches, are commonly characterized by wide-shallow platforms with rough surface and steep slopes which sharply drop into deep water. Hydrodynamic processes are therefore more complicated due to the interaction between surface waves and the complex reef topographies. Although numerous spectral models have succeeded in predicting wave height and wave setup over reefs, the accuracy in low-frequency infragravity waves, known to be the dominant wave components on shallow reefs, remains as one of the most challenge. This is because the mechanism of nonlinear wave-wave interactions is poorly resolved in these models. The aim of this project is to study wave transformation over reefs by a fully nonlinear wave model FUNWAVE-TVD based on Boussinesq equations. Influences of tidal levels, reef slopes and the roughness of bottom on wave spectral transformation over reefs have be investigated by comparing with the one-dimensional laboratory experiments. The model capability in simulating the evolution and dissipation of infragravity motions over reefs have be evaluated as well. The model results are found to be in good agreement with the laboratory observations. Furthermore, the model will be used to study spatial variations of waves and wave-induced currents with two-dimensional laboratory experiments. With refining the parameterization and systematic evaluations, the model will be applied to waves and circulations in real coral reef environments. It can be used to evaluate the effects of coastal engineering and coastal flooding due to climate change on reef environments.

Keyword(s)

珊瑚礁
氣候變遷
波譜
亞重力波
波揚
流場
Coral reef
climate change
wave spectra
infragravity waves
wave setup
nearshore circulation

DSpace CRIS

Numerical Study of Wave Spectrum Transformation over Fringing Coral Reefs(2)

基本資料

Description