同步入水双圆柱相互作用的计算研究

Computational Analysis of Interaction for Twin Cylinders during Synchronous Water Entry

为了研究多圆柱入水的相互影响,采用二维CFD方法数值模拟双圆柱同步常速入水物理过程。利用自由液面捕捉法来计算自由液面,将自由液面当作密度域的接触间断来处理,以非均匀密度的不可压缩Euler方程作为控制方程。采用直角切割网格作为离散网格系统和有限体积法进行数值离散,以人工压缩法来实现速度和压力的耦合求解,采用Roe的近似Riemann解算子计算流函数和一阶隐式的双时间推进法进行时间步进。以三个不同参数的双圆柱入水作为算例,将数值模拟得到的自由液面形状、圆柱压强分布和受力时间历程与单圆柱入水的结果进行了比较。

In order to study the interaction of cylinders during synchronous water entry,the hydrodynamic problem of twin cylinders entering water vertically at constant speed was numerically simulated based on 2D CFD method.Free surface capturing method was adopted to deal with free surface and the governing equations were the incompressible Euler equations for a variable density fluid field with a free surface,which was treated as a contact discontinuity.Cartesian cut cell mesh system was applied to solve moving boundary problem conveniently.On this basis,the FVM was introduced on spatial discretization and artificial compressible method was used for coupling calculation between fluid velocity and pressure.Numerical flux was calculated by Roe＇s approximate Riemann solver,and the implicit dual time-stepping technique was used for time advancing.Three water-entry cases of twin cylinders with different parameters were simulated.The free surface profile,pressure distribution and force of cylinders were computed and compared with those obtained from a single cylinder,and the interaction effect was investigated.