复杂来流对方形桥墩的冲击作用分析
发布时间：2018-07-17 02:52
【摘要】：随着经济社会的快速发展,桥墩形状从方形到圆形和椭圆形的转变对桥墩受力影响是一个值得研究的工程问题。实际工程中,桥墩多处在非均匀流场中,而目前对钝体绕流的研究多集中在均匀来流条件下,来流从均匀流转变为非均匀流时,结构物流场结构及升、阻力将发生很大变化。本文将对流出口边界条件引入特征线算子分裂有限元法中,建立了线性剪切来流的方柱绕流数值模型,对剪切流的方柱绕流及椭圆形桥墩绕流进行了分析。数值模拟了雷诺数Re=100、剪切参数k=0.0~0.5单方柱绕流,结果表明,k对方柱绕流尾部形成的两排涡影响明显;涡脱落在k较大时被抑制,在k≥0.4时涡量最终形成一个类似三角形的区域;驻点随k的增加逐渐向高速侧分离点移动,在k≥0.3时驻点的位置不再发生变化;平均阻力系数在0.2≤k≤0.25时发生较大变化,平均升力系数在k≥0.2时为负。对Re=100、k=0~0.4的串列双方柱绕流计算结果表明,间距比S/D(S为两方柱中心距离,D为方柱边长)和k对串列双方柱绕流流场结构、受力参数、方柱表面压力和升、阻力相图影响明显;均匀来流条件下串列双方柱间隙内流场稳定性与该区域内(?)m((?)m代表X轴方向上速度分量在一个振动周期内的时间平均速度)为负的区域是否连续有关,而剪切来流条件下此关系不成立;结合流场结构及压力云图分析得出k=0、0.1时临界间距区间分别为S/D=4~5和S/D=3~4。椭圆形桥墩绕流研究表明,随L/d(L为椭圆形桥墩前后圆弧中心距离,d为椭圆形桥墩圆弧直径)的增大,平均阻力系数(?)D随L/d先减小后增大,升力系数幅值CL和斯特劳哈数St随L/d增大而减小。
[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，
本文编号：2128688
[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，
本文编号：2128688
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