在斜坡海岸矩形橋面板之波浪負載;Hydrodynamic Loads of Rectangular Decks near a Sloped Beach

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Title:	在斜坡海岸矩形橋面板之波浪負載;Hydrodynamic Loads of Rectangular Decks near a Sloped Beach
Authors:	陳孟賢;Chen, Meng-Hsien
Contributors:	土木工程學系
Keywords:	波浪負載;橋面板;大渦模式;阻力係數;升力係數;Wave loads;Bridge deck;Sloped beach;Large Eddy Simulation model;Drag coefficient;Lift coefficient
Date:	2023-07-27
Issue Date:	2024-09-19 14:41:24 (UTC+8)
Publisher:	國立中央大學
Abstract:	當波浪撞擊到海岸邊橋梁時，對橋面板產生的巨大衝擊力是設計海岸橋梁時必須考量的重要參數。本研究使用水槽模型實驗和數值模式來研究孤立波撞擊到在斜坡海岸旁矩形橋面板的波浪力，流場模擬採用大渦流模式，並利用流體體積法來計算自由水面的變化，模擬結果之波高變化與水槽實驗結果十分吻合。再利用一系列的數值模擬，探討波高、水深、潛沒比以及斜坡坡度對波浪沖擊力的影響。模擬結果顯示，隨著潛沒比降低，橋面板上方的碎波更為明顯，橋面板上方的動壓、波浪力與橋面上孤立波的波高成線性正比關係。在斜坡海岸案例中，溯升過程中的波浪沖擊力大於溯降的波浪荷載，且橋面板距離岸邊越近，受到斜坡的影響越大，橋面板所受的波浪荷載也越大。並可藉由無因次係數計算橋面板所受到的水平向和垂直向的波浪力，工程設計可以使用最大阻力係數CD = 0.58，升力係數CL = 0.45，彎矩係數Cm = -0.21來計算海岸橋樑所受到的波浪荷載。;This study utilizes laboratory experiments and a numerical model to investigate the wave loads of solitary waves on a rectangular bridge deck near a sloped beach. The flow fields and surface waves are simulated by a integrated model of Large Eddy Simulation (LES) and the Volume of Fluid (VOF) method. The simulation results compared favorably with experimental results of wave flumes. Subsequently, the numerical model is used to examine influences of wave height, water depth, submergence, and slope angle on the wave loads of the bridge deck by a series of numerical simulations. The simulation results revealed that as the submergence ratio decreases, wave breaking above the deck becomes more pronounced and the wave loads are linearly proportional to the wave height above the bridge deck. In the case of a sloped beach, wave load during the runup stage is larger than that during the rundown stage. Increasing proximity of the bridge deck to the shore results in a greater influence from the sloped beach, leading to larger wave loads acting on the bridge deck. The horizontal and vertical forces acting on the deck can be computed by a dimensionless force coefficients. The maximum drag coefficient CD = 0.58, lift coefficient CL = 0.45, and pitching moment coefficient Cm = -0.21 can be used to compute the wave loads of bridge decks in the coastal regions.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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