Investigation on the Characteristics of Wave Dissipation and Flow Field Fluctuation by Stepped Submerged Embankment

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Project title

Code/計畫編號

MOST107-2221-E236-001

Translated Name/計畫中文名

波浪作用於階梯型沒水潛堤之消能特性暨二維波動流場變化之研究

Project Coordinator/計畫主持人

Ruey-Syan Shih

Funding Organization/主管機關

National Science and Technology Center for Disaster Reduction

Department/Unit

Department of construction and spatial design, Tungnan University

Website

https://www.grb.gov.tw/search/planDetail?id=12686418

Year

2018

Start date/計畫起

01-08-2018

Expected Completion/計畫迄

31-07-2019

Bugetid/研究經費

517千元

ResearchField/研究領域

土木水利工程

本研究計畫擬利用2年的時間分別利用水工模型試驗及數值模擬方式來探討階梯型粗糙堤面的消能與潛堤附近之流場特性，同時以規則波及不規則入射波浪條件來研究各種不同階梯型外形與粗糙度堤面的消能差異與效果，依序以單一潛堤及系列潛堤組合方式來進行試驗。本研究之階梯形狀與傳統僅具有固定水平與垂直面之階梯不同，與鋸齒較相似，外堤面與堤頂因不同階梯角度與入射波浪會有不同的交互作用結果，階梯形狀所產生的差異性以水工試驗分析波浪之透過率、反射率及消能特性與效果來分析與比較。對於水工實驗較難量測之水分子運動與速度場變化部分，研究計畫擬進一步在第2年以數值模擬之方式探討不同階梯形狀在潛堤領域附近所產生的流場變化與差異性。包括波浪通過不同間距之系列潛堤後所產生的渦流現象及速度場的變化，以便探討作用區域水面波形變化、速度場與水分子之運動軌跡，以及波浪通過任意高度遞增潛堤、潛堤組間距等所產生的反射波及交互作用下內部速度場的研究。數值研究結果將有助於結構物附近臨底輸砂特性之研究，而交互作用區內水粒子的運動軌跡更有助於漂砂運動的研究與評估，可做為研究近海地區結構物受波浪影響所造成的海岸變遷與海底地形變化的研究基礎，無論是在學術研究或實際工程之應用上均具有實質上的意義。水工模型試驗部份最後再以3種不同流速之順向流與逆向流條件進行上列試驗，分析波浪受順向流及逆向流影響下與沒水結構物交互作用後之各項物理量的影響。 This two-year project intends to study the wave energy dissipation characteristics and the variations of flow field of a single stepped embankment and a series of stepped embankment set using both the hydraulic model tests and numerical simulation methods, which would be carried out using regular waves and irregular waves. One of the main purposes is to study the variations of energy dissipation effects under a variety of step shapes and roughness surfaces of the embankment in accordance of a single submerged embankment and a series of submerged embankments. The present stepped obstacle is different from a traditional stepped dike with fixed horizontal and vertical stage surface as previously investigated by many experts and scholars, the angle of the present stepped surface varies with the slope of the embankment surface, with various interaction angles between the incident waves and the rough stepped surfaces. The wave and wave field characteristics in the shallow water region cause by periodic waves and solitary waves are analyzed by the two-phase flow model. The variations of water surface waveform, the velocity field and the trajectory of water molecules are also discussed.Finally, in the hydraulic model test, a forward and reversed flow with different flow velocities would be adopted, to investigate the wave attenuation physical quantities of the stepped embankments which are also influenced by the flow. The motion trajectories of the water particles in the interaction zone contribute to the research and evaluation of the sand drift movement as a basis for studying the coastal changes and seabed topographic changes in coastal structures, whether in academic research or practical application of the project are of substantial significance.

Keyword(s)

水工模型試驗
兩相流
數值水槽
速度場
階梯型潛堤
規則波
不規則波
Hydraulic model test
two-phase flow
numerical water tank
velocity field
stepped embankment
regular wave
irregular wave

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Investigation on the Characteristics of Wave Dissipation and Flow Field Fluctuation by Stepped Submerged Embankment

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