一种几何VOF方法在液舱晃荡流动模拟中的应用

Application of a Geometric VOF Method in the Simulations of Sloshing Flow

isoAdvector是一种新的几何VOF(Volume of Fluid)方法,虽然克服了传统几何VOF方法难以适用于三维空间任意多面体网格的缺点,但不能直接用来模拟涉及动网格技术的液舱晃荡.为此,引入了运动通量修正,并提出了面-界面交线运动修正,使得修正后的isoAdvector方法可以应用到液舱晃荡的模拟中.基于不同的VOF方法对非共振、共振受迫晃荡和单次冲击波面进行数值模拟,并将模拟结果与试验结果以及解析解进行了比较.结果表明:相对于代数VOF方法,采用修正后的isoAdvector方法获得的自由液面位置和整体水动力载荷精度更高;捕捉的波面没有褶皱,能够较好地模拟波面的翻卷和破碎.此外,提出了界面厚度的估计方法,分析了自由液面波高精度提高的原因.

The isoAdvector method is a new geometric volume of fluid(VOF)method.It overcomes the difficulties that the traditional geometric VOF methods cannot be applied on arbitrary polyhedral meshes.However,the isoAdvector method cannot be directly applied to sloshing simulations which involve the dynamic mesh technique.Thus,the motion flux correction is introduced,and the velocity correction for face-interface intersection line is proposed.The modified isoAdvector method can then be applied to the sloshing simulations.The non-resonant and the resonant sloshing under forced excitations and the single impace wave are simulated based on different VOF methods,and the results are compared with the experiments and the analytical solution.It demonstrates that the modified isoAdvector method can provide more accurate positions of the free surface and the hydrodynamic loads than the algebraic VOF method.In addition,the wave overturning and breaking can be predicted well without the wrinkles on the wave surface by using the modified isoAdvector method.A new approach for evaluating the interface thickness is proposed to analyze the reason for the improvement of the accuracy of free-surface elevations.