曲壁面两相流的简单扩散界面浸没边界法

A simple diffuse interface immersed-boundary scheme for binary flows with curved boundaries

针对在欧拉-拉格朗日网格框架下曲边界上的两相流润湿边界条件实施问题,本文提出了一种简单扩散界面浸没边界法。在此方法的框架下,静止和移动曲边界的湿润边界条件都可以采用平板边界方式处理。在该方法中,我们在实际边界内外一个拉格朗日网格间距处添加了两层虚拟贴体拉格朗日网格,并通过插值得到三层拉格朗日点上的序参数,从而得到实际的曲边界润湿条件。该方案实施思路简单,不仅适用于静止曲边界,还适用于复杂的运动曲边界。为了验证该方法的有效性,本文在广义守恒相场格子玻尔兹曼方法(LBM)框架下,模拟了静态液滴在圆柱上的铺展、动态液滴撞击圆柱、圆柱在水池中沉降三个问题。结果表明该方法能够有效地模拟曲面上的两相流动,具有良好的精度、鲁棒性和质量守恒性。

In this paper,a simple diffuse interface immersed-boundary scheme is developed for binary flows with curved boundaries under the frame of Euler-Lagrangian meshes.By this mean,the wetting boundary conditions(WBC)for stationary and moving curved boundaries can also be dealt in a similar manner as the flat boundaries.The main idea is cultivated by introducing two virtual layers of Lagrangian grid inside and outside the exact curved boundary with one interval of two neigboring lagrangian points,and the WBC is realized by the order parameters at the Lagrangian points,which are interpolated from the Euler grids.This scheme has the advantage of simple implication,it can successfully accommodate both the stationery and complex moving curved boundaries along with good accuracy and mass conservation property.A lattice Boltzmann method(LBM)framework is developed to incorporate the proposed immersed-boundary scheme.To test the present method,several binary flow problems are simulated.The numerical results are compared with theoretical and experimental results from literature which showed that the method can easily and efficiently simulate two-phase flows on the curved surfaces with high accuracy and mass conservation properties.