發(fā)布時間：2018-07-17 02:52

【摘要】：隨著經(jīng)濟(jì)社會的快速發(fā)展,橋墩形狀從方形到圓形和橢圓形的轉(zhuǎn)變對橋墩受力影響是一個值得研究的工程問題。實(shí)際工程中,橋墩多處在非均勻流場中,而目前對鈍體繞流的研究多集中在均勻來流條件下,來流從均勻流轉(zhuǎn)變?yōu)榉蔷鶆蛄鲿r,結(jié)構(gòu)物流場結(jié)構(gòu)及升、阻力將發(fā)生很大變化。本文將對流出口邊界條件引入特征線算子分裂有限元法中,建立了線性剪切來流的方柱繞流數(shù)值模型,對剪切流的方柱繞流及橢圓形橋墩繞流進(jìn)行了分析。數(shù)值模擬了雷諾數(shù)Re=100、剪切參數(shù)k=0.0~0.5單方柱繞流,結(jié)果表明,k對方柱繞流尾部形成的兩排渦影響明顯;渦脫落在k較大時被抑制,在k≥0.4時渦量最終形成一個類似三角形的區(qū)域;駐點(diǎn)隨k的增加逐漸向高速側(cè)分離點(diǎn)移動,在k≥0.3時駐點(diǎn)的位置不再發(fā)生變化;平均阻力系數(shù)在0.2≤k≤0.25時發(fā)生較大變化,平均升力系數(shù)在k≥0.2時為負(fù)。對Re=100、k=0~0.4的串列雙方柱繞流計算結(jié)果表明,間距比S/D(S為兩方柱中心距離,D為方柱邊長)和k對串列雙方柱繞流流場結(jié)構(gòu)、受力參數(shù)、方柱表面壓力和升、阻力相圖影響明顯;均勻來流條件下串列雙方柱間隙內(nèi)流場穩(wěn)定性與該區(qū)域內(nèi)(?)m((?)m代表X軸方向上速度分量在一個振動周期內(nèi)的時間平均速度)為負(fù)的區(qū)域是否連續(xù)有關(guān),而剪切來流條件下此關(guān)系不成立;結(jié)合流場結(jié)構(gòu)及壓力云圖分析得出k=0、0.1時臨界間距區(qū)間分別為S/D=4~5和S/D=3~4。橢圓形橋墩繞流研究表明,隨L/d(L為橢圓形橋墩前后圓弧中心距離,d為橢圓形橋墩圓弧直徑)的增大,平均阻力系數(shù)(?)D隨L/d先減小后增大,升力系數(shù)幅值CL和斯特勞哈數(shù)St隨L/d增大而減小。
[Abstract]:With the rapid development of economy and society, the change of pier shape from square to round and ellipse is an engineering problem worth studying. In practical engineering, many piers are located in the non-uniform flow field, but the current research on the flow around the blunt body is mostly focused on the uniform flow condition. When the incoming flow changes from uniform flow to non-uniform flow, the structure and lift of the structure logistics field and the resistance will change greatly. In this paper, the convection exit boundary condition is introduced into the characteristic line operator splitting finite element method, and the numerical model of the linear shear flow around the square cylinder is established, and the flow around the square column and the elliptical pier of the shear flow is analyzed. The numerical simulation results show that the two rows of vortices formed in the tail of the flow around the flow are obviously affected, the vortex shedding is restrained when k is larger, and when k 鈮，

本文編號：2128688