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    Please use this identifier to cite or link to this item: https://tkuir.lib.tku.edu.tw/dspace/handle/987654321/74487

    Title: 圓柱橋墩結構之計算流體力學模擬研究
    Other Titles: The study of computationa fluid dynamics on cylindrical piers structure
    Authors: 鄭凱仁;Cheng, Kai-Jen
    Contributors: 淡江大學土木工程學系碩士班
    張正興;Chang, Cheng-Hsin
    Keywords: CFD;k-ε;V.O.F
    Date: 2011
    Issue Date: 2011-12-28 18:44:23 (UTC+8)
    Abstract: 颱風來襲時洪水挾帶泥沙、土石使得橋墩沖刷,斷橋事件頻傳。過度的盜採砂石,使得下游橋墩造成不平衡沖刷,危及橋樑下部結構,當洪水侵襲時便造成橋墩損壞。水工結構物造成水理特性的改變而造成橋墩周圍底床形成倒錐形的局部沖刷。對於水利工程方面多半以水工試驗作為研究主體,搭配數值模擬做驗證,但多半為討論流場及沖刷深度的變化。本研究希望透過CFD模擬出 三維流場中橋墩周圍流場及橋墩之受力情形,在省時省力情況下提供初步評估。

    本研究數值模擬分為兩部分;第一部分為數值模型驗證部分以四種模式紊流模式Standard k- ε、RNG k- ε 、realizable k- ε 、RSM進行流場模擬,並與試驗數據比較。第二部分則進行不同流場條件之數值模擬,並討論橋墩周維流場及橋墩受力情況。

    This study is divided into two parts, the first part is validating numerical models using four kinds of turbulence models (standard k-ε, RNG k-ε, realizable k-εand RSM) to simulate the flow field around bridge piers and to compare the results of the four models with experimental data. The better model was chosen for the second part of the research. The second part is setting different boundary conditions to run numerical simulations. In this part, the characteristics of the flow field around bridge piers and the stress on the piers were studies and discussed.
    Before hydraulic tests, software "Fluent" can be used to simulate the flow field around bridge piers to obtain flow field characteristic data (e.g., velocity and pressure distribution), and simulated bed shear stress can be used to estimate the scour depth around piers. When the results of numerical simulation match the data from previous hydraulic tests, unmeasured locations can be investigated using numerical simulations. In hydraulic tests, the focuses are on the characteristic of flow field and scour depth, and usually not enough data regarding the forces on the piers. Therefore, in this study, different boundary conditions (e.g., flow depth, velocity and bed shape) were used in the numerical simulations and analysis of the forces on the piers. It is hoped that the results of this thesis can be extended in the future to simulate the loading condition of piers subjected to flood impact.
    Appears in Collections:[Graduate Institute & Department of Civil Engineering] Thesis

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