本文關(guān)鍵詞： 方柱 矩形斷面 橋下凈高 主梁 氣動(dòng)特性 CFD SSTk-ω模型　出處：《湖南大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：大跨度橋梁由于結(jié)構(gòu)形式和地形條件不同可能具有不同的橋下凈高�？绾訕蛄涸谟昙竞涂菟久媾R顯著的水面漲落，，跨海大橋受到氣候和洋流等的影響，海面高度也會(huì)發(fā)生改變，這些因素都能夠使得橋梁下部?jī)舾弋a(chǎn)生明顯變化。大跨度橋梁結(jié)構(gòu)柔度大，對(duì)風(fēng)的作用敏感，因此這種由于橋下凈高變化而產(chǎn)生的對(duì)橋梁主梁氣動(dòng)特性的影響在設(shè)計(jì)時(shí)不得不進(jìn)行考慮。目前對(duì)這一問題的研究成果不多，因此本文對(duì)此進(jìn)行研究，具體是通過計(jì)算流體動(dòng)力學(xué)(CFD)方法，進(jìn)行二維數(shù)值模擬分析。 首先，對(duì)方柱繞流進(jìn)行了二維數(shù)值模擬，以驗(yàn)證本文計(jì)算方法的合理性。得到了方柱三分力系數(shù)、渦脫斯托羅哈數(shù)St、方柱表面風(fēng)壓系數(shù)分布和流場(chǎng)特性等結(jié)果。計(jì)算結(jié)果與風(fēng)洞試驗(yàn)吻合較好，表明本文采用的SSTk湍流模型具有良好的精度。對(duì)方柱繞流的雷諾數(shù)效應(yīng)進(jìn)行數(shù)值模擬，結(jié)果表明在1.0×103到1.0×105量級(jí)內(nèi)，雷諾數(shù)效應(yīng)不明顯。 然后，研究邊界條件對(duì)矩形截面主梁氣動(dòng)特性的影響。選取寬高比為5的矩形截面主梁為研究對(duì)象，對(duì)不同橋下凈高時(shí)，矩形截面主梁的繞流進(jìn)行二維數(shù)值模擬。計(jì)算得到了矩形截面主梁三分力系數(shù)、渦脫斯托羅哈數(shù)St、矩形表面風(fēng)壓系數(shù)分布和流場(chǎng)特性等結(jié)果。對(duì)比各工況結(jié)果，定量分析了橋下凈高對(duì)矩形截面主梁氣動(dòng)特性的具體影響。 最后，研究橋下凈高對(duì)大跨橋梁主梁氣動(dòng)特性的影響。選取某實(shí)橋閉口流線型鋼箱梁斷面為研究對(duì)象，對(duì)不同橋下凈高下，橋梁主梁氣動(dòng)特性進(jìn)行了二維數(shù)值模擬。計(jì)算得到不同橋下凈高時(shí)，橋梁主梁斷面三分力系數(shù)、渦脫斯托羅哈數(shù)St、橋梁主梁斷面表面風(fēng)壓系數(shù)分布和流場(chǎng)特性等結(jié)果。對(duì)比不同橋下凈高下的結(jié)果，定量分析了橋下凈高對(duì)大跨橋梁主梁氣動(dòng)特性的具體影響。
[Abstract]:Long span bridges may have different net height under the bridge because of the different structural form and terrain conditions. The bridge beams are faced with significant fluctuations in the rainy season and dry season, and the bridge across the sea is affected by climate and ocean currents. The sea surface height will also change, these factors can make the bridge lower net height change obviously. Large span bridge structure flexibility, sensitive to the role of the wind. Therefore, the influence on the aerodynamic characteristics of the bridge girder caused by the change of the net height under the bridge has to be considered in the design. Two-dimensional numerical simulation is carried out by computational fluid dynamics (CFD) method. Firstly, two-dimensional numerical simulation is carried out to verify the reasonableness of the proposed method. The three-point force coefficient of the square column and the vortex de-Storoha number St are obtained. The results of wind pressure coefficient distribution and flow field characteristics on the square column surface are in good agreement with the wind tunnel test. It is shown that the SSTk turbulence model adopted in this paper has a good accuracy. The Reynolds number effect over a cylinder is numerically simulated, and the results show that it is in the order of 1.0 脳 10 ~ 3 to 1.0 脳 10 ~ 5. The Reynolds number effect is not obvious. Then, the influence of boundary conditions on the aerodynamic characteristics of rectangular cross-section main beam is studied. The rectangular cross-section main beam with ratio of width to height of 5 is selected as the research object, and the net height under different bridges is also studied. Two-dimensional numerical simulation of the flow around the main beam with rectangular section is carried out. The three-point force coefficient of the main beam with rectangular section and the vortex de-StoRoha number St are calculated. The results of wind pressure coefficient distribution and flow field characteristics on the rectangular surface are compared and the effects of net height under the bridge on the aerodynamic characteristics of the main beam with rectangular section are quantitatively analyzed. Finally, the effect of net height under the bridge on the aerodynamic characteristics of the main girder of the long-span bridge is studied. The section of a steel box girder with closed mouth is selected as the research object, and the net height under the bridge is reduced. The aerodynamic characteristics of the main girder of the bridge are numerically simulated in two dimensions. When the net height under the bridge is different, the cross-section force coefficient of the main girder and the vortex de-StoRoha number St are calculated. The results of wind pressure coefficient distribution and flow field characteristics on the surface of the main girder of the bridge are compared with the results of the net height under different bridges, and the specific effects of the net height under the bridge on the aerodynamic characteristics of the main girder of the long-span bridge are quantitatively analyzed.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U441.3

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本文編號(hào)：1470993