發(fā)布時間：2018-06-22 16:51

  本文選題：橋梁結構 + 三分力系數(shù)��； 參考：《湖南大學》2014年碩士論文

【摘要】：近年來，隨著計算流體力學理論的完善和計算機技術的發(fā)展，基于計算流體動力學(CFD)的數(shù)值方法迅速成熟，雖然還不能代替風洞試驗，但相比于傳統(tǒng)的抗風研究方法有其獨特的優(yōu)勢，由于該方法設計周期短、試驗費用低、承擔風險小，流動可視化易于實現(xiàn)等，已經(jīng)成為研究橋梁風效應問題的一種有效手段。本文即借助計算流體動力學方法對橋梁風效應進行研究。 (1)以澧水大橋為工程背景，應用SST k-湍流模型，數(shù)值模擬不同攻角下主梁斷面的三分力系數(shù)，提取計算結果與試驗值進行對比，給出了主梁斷面周圍流場的壓強與速度分布圖并進行分析，進一步驗證了CFD能夠較為精確的數(shù)值模擬主梁斷面的三分力系數(shù)及具有顯示流體流動方面的優(yōu)越性。 (2)采用計算流體力學軟件FLUENT中的雷諾平均方法(RANS)的SST k-湍流模型求解不可壓粘性流體納維斯托克斯(N-S)方程。將二維矩形柱體簡化為質量-彈簧-阻尼系統(tǒng)。網(wǎng)格建立過程中運用“剛性運動區(qū)域+動網(wǎng)格區(qū)域+靜止網(wǎng)格區(qū)域”的方法首先對其進行分塊，然后將Newmark-法代碼編寫入FLUENT的用戶自定義函數(shù)(UDF)中對結構的振動響應進行求解，結合FLUENT軟件中的動網(wǎng)格技術建立了結構渦振數(shù)值模擬方法。以寬高比為6的矩形斷面為研究對象，對其在不同風速條件下進行繞流和渦振數(shù)值模擬，研究結果顯示：渦激振動“鎖定”區(qū)間和渦振響應振幅的數(shù)值模擬結果與風洞試驗結果吻合良好；表明采用該方法進行具有分離、再附著現(xiàn)象的鈍體斷面渦激振動是可行的。 (3)采用歐拉—歐拉體系的兩相流理論，將雨滴場作為連續(xù)介質場，在流體計算軟件FLUENT基礎上編寫了相應的UDF計算程序，對矩形柱體周圍的風雨運動進行三維數(shù)值模擬。采用雷諾平均方法得到了在不同雨相粒徑、不同風速下的雨相流線圖，模型表面的雨滴捕獲率、沖擊荷載等。采用大渦模擬方法得到順風向、橫風向和扭轉向的荷載時程數(shù)據(jù)和力譜，并與無雨時作對比，發(fā)現(xiàn)風驅雨對模型靜態(tài)荷載影響很小，對動態(tài)荷載的影響較大，但平均效應很小。 與風洞試驗相比，用CFD數(shù)值模擬方法研究橋梁風效應問題，不需要昂貴的風洞試驗設備和測量儀器，也不需模型的制作，，并且該方法的可重復性很好，不具有風洞試驗周期長、費用高等問題。數(shù)值模擬方法可以實現(xiàn)氣動選型和對模型的參數(shù)識別。
[Abstract]:In recent years, with the improvement of computational fluid mechanics theory and the development of computer technology, the numerical method based on computational fluid dynamics (CFD) is rapidly mature. Although it can not replace the wind tunnel test, it has its unique advantages compared with the traditional wind resistance research method. Because the design period is short, the cost of the experiment is low, the risk is small, and the flow is small. The dynamic visualization has become an effective means to study the wind effect of bridge beams. In this paper, the wind effect of bridge is studied with the help of computational fluid dynamics.
(1) Taking Lishui bridge as the engineering background, the SST k- turbulence model is applied to simulate the three division coefficient of the main beam section under different angle of attack. The calculation results are compared with the experimental values, and the pressure and velocity distribution map of the flow field around the main beam is given and analyzed, and the more accurate numerical simulation of the main beam broken by CFD is verified. The three component coefficient of surface and its superiority in displaying fluid flow.
(2) the SST k- turbulence model of the Reynolds mean method (RANS) in the computational fluid dynamics software FLUENT is used to solve the incompressible viscous fluid nvius tox (N-S) equation. The two-dimensional rectangular column is simplified to a mass spring damping system. The method of "rigid moving area + dynamic grid region + static grid area" is used in the process of grid establishment. First, we block it, then write the Newmark- code into FLUENT's user custom function (UDF) to solve the vibration response of the structure, and establish a numerical simulation method of structure vortex vibration with the dynamic grid technology in the FLUENT software. The rectangular section with the width height ratio of 6 is studied under different wind speed conditions. The numerical simulation of flow around and vortex vibration shows that the numerical simulation results of the "locking" interval and the vibration response amplitude of the vortex excited vibration are in good agreement with the wind tunnel test results, which shows that it is feasible to use this method to carry out the vortex excited vibration of the blunt body section with separation and reattachment.
(3) using the theory of two phase flow in Euler Euler system, using the raindrop field as a continuous medium field, the corresponding UDF program is written on the basis of the fluid calculation software FLUENT. The three-dimensional numerical simulation of wind and rain movement around the rectangular column is carried out. The rain flow lines under the different rain phase particle size and different wind speed are obtained by the Reynolds mean method. Figure, the raindrop capture rate and impact load on the surface of the model. Using the large eddy simulation method, the load time data and force spectrum of the wind direction, the transverse wind direction and the torsional steering are obtained, and compared with the rain free time, it is found that the wind drive rain has little influence on the static load of the model, and the dynamic load has great influence on the dynamic load, but the average effect is small.
Compared with the wind tunnel test, using the CFD numerical simulation method to study the wind effect of the bridge beam does not require expensive wind tunnel test equipment and measuring instruments, and does not need the model, and the repeatability of the method is very good. It does not have long wind tunnel test period and high cost. The numerical simulation method can realize pneumatic selection and model reference. Number identification.
【學位授予單位】：湖南大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U441

【參考文獻】

相關期刊論文 前10條

1 徐楓;歐進萍;;方柱非定常繞流與渦激振動的數(shù)值模擬[J];東南大學學報(自然科學版);2005年S1期

2 譚紅霞;陳政清;;CFD在橋梁斷面靜力三分力系數(shù)計算中的應用[J];工程力學;2009年11期

3 劉志文;胡建華;陳政清;龍海濱;;閉口箱形主梁斷面三分力系數(shù)二維大渦模擬[J];公路交通科技;2011年11期

4 劉學強,伍貽兆,夏健;用混合網(wǎng)格求解三維可壓雷諾平均Navier-Stokes方程[J];計算力學學報;2002年03期

5 王美蓮;;橋梁風工程研究探討[J];山西建筑;2012年01期

6 曹豐產(chǎn),項海帆,陳艾榮;橋梁斷面的氣動導數(shù)和顫振臨界風速的數(shù)值計算[J];空氣動力學學報;2000年01期

7 李廣望,任安祿,陳文曲;ALE方法求解圓柱的渦致振動[J];空氣動力學學報;2004年03期

8 楊俊濤;樓文娟;;風驅雨CFD模擬及平均雨荷載計算方法研究[J];空氣動力學學報;2011年05期

9 賀德馨;我國風工程研究現(xiàn)狀與展望[J];力學與實踐;2002年04期

10 趙國智;孔凡讓;占驚春;張志偉;柴華;;基于SIMPLE算法的湍流場數(shù)值模擬[J];水電能源科學;2007年03期

相關博士學位論文 前1條

1 盧春玲;復雜超高層及大跨度屋蓋建筑結構風效應的數(shù)值風洞研究[D];湖南大學;2012年

本文編號：2053513