海啸数值模拟及桥梁上部结构冲击动力作用研究

Numerical simulation of tsunami and dynamic impact of bridge superstructure

海啸作为一种破坏力较强的海洋灾害,对近海桥梁的威胁不言而喻。上部梁体作为常规桥梁的重要组成部分,其在海啸冲击下的数值模拟研究受到了广大学者的关注。文中利用溃坝波模拟海啸波,在Fluent软件中建立上部梁体数值模型,该模型耦合VOF法和k-ε湍流模型求解雷诺平均N-S方程,并采用PISO算法进行数值迭代。从计算域设置、网格划分和湍流模型选定对数值模型基本情况进行说明,然后对数值结果进行分析,并利用已有试验数据,验证溃坝波冲击下上部梁体数值模型运行结果的准确性。结果表明:若将上部梁体变形耗能差异考虑在内,数值模拟下的溃坝涌波水平力满足试验要求;而对于溃坝涌波竖向力,除了在初始突变段时试验与数值结果有些差别外,在之后的似平稳段大致相同。

As a destructive marine disaster,the threat of tsunami to offshore bridges is self-evident. Besides,superstructure is an important part of conventional bridge and thus the numerical simulation of the superstructure under the impact of tsunami is focused by many researchers. In this paper,the dam-break wave is used to simulate the tsunami wave,and the numerical model of the superstructure is established by Fluent. The model solves the Reynolds average Navier-Stokes equations by using volume of fluid method and k-ε turbulence model,and the PISO algorithm is used for numerical iteration. The basic situation of the numerical model is illustrated from the setting of calculation domain,mesh generation and selection of turbulence model,then the numerical results are analyzed.Moreover,combined with experimental results,the accuracy of the numerical model results for the superstructure under the impact of dam-break wave is verified. The analysis results indicate that the horizontal force of dam-break wave under numerical simulation will meet the experimental requirements if the difference of deformation energy consumption of superstructure is taken into account. As for vertical force of dam-break wave,the experimental and numerical results are roughly the same in the quasi-stationary stage,except for some difference in the initial mutation stage.