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研究生: 吳憶茹
Yi-Ru Wu
論文名稱: 大渦模擬研究隔板對於水箱內液面擺盪之影響
Large Eddy Simulation of Liquid Sloshing in a Tank with Baffles
指導教授: 朱佳仁
Chia-Ren Chu
口試委員:
學位類別: 碩士
Master
系所名稱: 工學院 - 土木工程學系
Department of Civil Engineering
論文出版年: 2016
畢業學年度: 104
語文別: 英文
論文頁數: 89
中文關鍵詞: 擺盪隔板大渦模式流體體積法
外文關鍵詞: Sloshing, Baffle, Large Eddy Simulation, Volume of Fluid
相關次數: 點閱:9下載:0
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  • 液體在容器內擺盪對儲油槽的設計和大樓液體阻尼器的減振效果都是一個很重要的問題,設計不良的儲油槽可能會被液體擺盪時所產生的動壓力而使得油槽變形、破壞等。因此,有些儲油槽會在內部裝設隔板來減緩液體的擺盪。本研究利用三維大渦流模式與振動台實驗水箱底部隔板的高度、間距和數量對於降低水面擺盪幅度的效果,並計算自由液面以及水體施予水箱壁面的壓力,以供工程設計的參考。數值模擬結果與實驗結果的驗證,以增加數值模擬的可信度。再利用數值模式有系統地探討振幅、水深比、隔板高度、間距及隔板數目等參數對水箱內波高及壁面所受壓力的影響。研究結果發現當隔板高度增加時,波高變小,但隔板高度與水深比增加至0.75時,波高則幾乎不再降低。而隔板數量增加時,波高亦隨之變小,但隔板數量增加至7個(隔板間距S/L = 0.15)以上時,波高也幾乎不再被減少。壁面所受的壓力亦隨著隔板數量而大幅減小,最大動壓發生在水面附近。


    Sloshing is essential to the design of storage tanks and liquid dampers in the high-rise buildings. External force gives the liquid kinetic energy in water tank to produce acceleration in the water tank and cause the liquid to slosh. Poorly designed tanks may be damaged by the dynamic pressure on the sidewalls. The vertical baffles on the tank bottom could reduce the sloshing in the storage tanks. This study uses a Large Eddy Simulation model and laboratory experiments to investigate the influences of baffle on the wave height in the tank. The simulation results were verified by the measured wave heights in a rectangular water tank on a shaking table. The results indicate that the wave frequency in the water tank is equal to the excitation frequency, and the maximum wave height occurs when the excitation frequency near the natural frequency of the tank. The simulation results also reveal that the wave height decreases as the baffle height or baffle number increase. But the influence of baffle height, hb, and baffle number, Nb, mitigated when the relative baffle height hb/hw ≥ 0.75 or baffle number Nb ≥ 5. The force coefficient on the sidewall also decreases when the baffle height and baffle number increase.

    Contents Abstract I Contents III Notation IV Figure captions V Table captions IX 1. Introduction 1 1.1 Motivation 1 1.2 Literature review 4 2. Numerical model 5 2.1 Turbulence model 5 2.2 Numerical scheme 7 3. Experimental setup 8 4. Model Validation 10 4.1 Without baffle 10 4.2 With baffles 12 5. Results and Discussion 14 5.1 Baffle height 14 5.2 Excitation frequency 14 5.3 Baffle spacing 15 5.4 Pressure force 16 6. Conclusions 18 References 20 Tables 22 Figures 31

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