| 摘要: |
| 桩柱绕流水动力特性直接决定水流对桩柱作用力的分布规律,是内河框架码头水流荷载计算的基础。结合计算流体动力学(CFD),开展了内河框架码头大直径桩柱串列及并列四桩柱绕流水动力特性的二维数值模拟,系统分析了不同流速及不同桩间距下桩柱绕流尾流流场形态,揭示了桩柱绕流阻力系数 、升力系数 、斯特劳哈数 随流速U、桩间距L的变化规律。研究表明：(1)随桩间距L的增大,串列四桩柱上游桩柱的边界层分离点位置逐渐后移,在L≥5D时,边界层分离点的位置基本不变, 数保持不变；在L≥7D时, 基本保持不变。(2)并列四桩柱,绕流流场对称,双圆柱绕流中的双稳现象消失,空隙水流流动始终偏向外侧,在L=2D～5D时,桩1、桩2流场的漩涡同步反相脱落,在L=7D～9D时,桩1、桩2的漩涡同步同相脱落,在L≥4D时,各桩柱绕流流场间的干扰基本可以忽略,系数 、 、 边界层分离点均保持不变。(3)串列桩柱的遮流影响效应在桩间距小时表现的更明显,L<4D时,遮流影响系数最大可达到2.12；在L≥7D时,遮流影响系数保持在0.6~0.7之间。(4)并列桩柱在L≥4D时,横向影响系数约为1.0,基本可以不考虑并列桩柱间流场横向系数的影响。研究成果可为类似内河框架码头水流荷载计算提供参考。 |
| 关键词: 内河框架码头 桩柱绕流 水动力特性 数值模拟 遮流影响系数 横向影响系数 |
| DOI： |
| 分类号:TV143 |
| 基金项目:国家自然科学基金资助项目(51479014)；重庆市社会民生科技创新专项项目(cstc2017shmsA1410)；四川省交通运输科技项目(2015B1-3) |
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| Two dimensional numerical simulation of hydrodynamic characteristics of series - parallel piles around flowing waterin inner river frame wharf |
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Liumingwei1, zengliqin2, Chen gang3, Shen Lilong2, Mou Zhizhong4, Wang Mingjing4
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1.Chongqing Jiaotong University;2.chongqingjiaotong university;3.Sichuan Provincial Transportation Department Traffic Investigation and Design Institute;4.Research Institute of Traffic Survey and Design, Sichuan Transportation Department
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| Abstract: |
| The hydrodynamic characteristics of the flow around the pile directly determine the distribution law of the flow force on the pile, which is the basis for the calculation of the flow load of the inland river hydraulic structure. Combined with computational fluid dynamic(CFD), two-dimensional numerical simulation of hydrodynamic characteristics of large diameter pile columns with four columns in series and four columns in parallel around flowing water inland framework wharf are carried out. The flow field patterns of the wake around the pile at different velocity and pile spacing are analyzed systematically. The variation law of the flow resistance coefficient and the lift coefficient and the strouhal number with the flow velocity U and the pile spacing L are revealed. Research shows that:(1) With the increase of the pile spacing L, the boundary point separation point of the piles in the upper part of the four piles is gradually moved back. For L≥5D, the position of the boundary layer separation point is basically unchanged and the number of remains unchanged. For L≥7D, is essentially the same. (2) For parallel four pile, symmetric around the flow field, double cylindrical flow around the bistable phenomenon disappears, space of flow to the lateral, when L=2D~5D, the vortex of the flow field of pile 1 and pile 2 falls off synchronously and reversely, when L=7D~9D, the vortex of the flow field of pile 1 and pile 2 is synchronously in phase. When L≥4D, the interference between the flow fields around each pile can be basically ignored, the interference between the coefficient of 、 、 boundary layer separation points remain unchanged.(3) The effect of blocking flow of series piles is more obvious when the pile spacing is small, when L<4D, the maximum influence coefficient of flow shielding can reach 2.12. When L≥7D, the influence coefficient of flow shielding is maintained between 0.6~0.7. (4) When L≥4D, the lateral influence coefficient of the parallel piles is about 1.0, and the influence of the lateral influence of the flow field between the parallel piles can be basically ignored. These research results can provide reference for the calculation of flow load of similar river frame wharf. |
| Key words: Inland river frame Wharf flow around pile hydrodynamic characteristics numerical simulation influence coefficient of flow shielding Lateral influence coefficient |
