基于拉格朗日体系的典型桥梁断面风-雨耦合作用数值模拟

Numerical Simulation of Wind-rain Coupling Effect on Typical Bridge Section Based on Lagrangian System

对典型桥梁断面风-雨耦合作用下的静三分力进行了CFD(Computational Fluid Dynamics)数值模拟研究.对计算流体动力学软件进行二次开发,采用DPM(Discrete Phase Model)模型结合UDF(User Defined Function)函数施加源项的方法来研究风-雨耦合作用对桥梁断面静三分力系数的影响.将空气作为连续相通过欧拉法求解,采用基于拉格朗日体系的离散相模型对雨滴运动轨迹进行求解,引入离散随机游走模型来考虑旋涡对雨滴运动的影响,并通过冲量定理得到风-雨耦合下的雨滴对主梁断面的冲击载荷.通过与文献结果比较来验证方法的正确性,然后研究了风-雨耦合作用对典型桥梁断面三分力系数的影响,以及三维风-雨耦合作用对典型桥梁断面的作用机理,为研究桥梁风-雨耦合荷载提供了基础理论方法.

The static coefficients of typical bridge section under the wind-rain coupling effect were stud- ied using the numerical simulation by CFD（Computational Fluid Dynamics） . Based on secondary development for the computational fluid dynamics software by applying source term, DPM（Discrete Phase Model） model combined with a UDF（User Defined Function） function method was used to study the wind-rain coupling effect on static coefficients of bridge.Meanwhile,Euler method was used to simulate the air phase and Lagrangian method was adopted to simulate the rain with discrete phase model. Impact load on the bridge section was obtained by the impulse theorem.The accuracy of the method was verified by comparing with the existing results in the corresponding literature.The wind-rain coupling effect on the static coeffi- cients of typical bridge section is then studied,and the mechanism research of wind-rain coupling on typical bridge section was realized, which provides a theoretical method for the study of the wind-rain coupling load on the bridge.