Development of the numerical method for interfacial dynamics with large density difference by the lattice kinetic scheme

本文首先利用晶格玻尔兹曼方法建立了具有大密度差的界面动力学的数值计算方法。其次，将该方法发展为晶格动力学格式，以减少计算时的内存大小。最后，在并行机上实现了该代码，并将其应用于实际问题的仿真。本研究的总结如下：1。提出了大密度差界面动力学的数值计算方法。将该方法应用于双液滴碰撞和气泡流动的模拟，以研究以下问题。-界面宽度对计算结果的影响。-流动性对计算结果的影响。-网格尺寸对计算结果的影响。该代码在并行机中实现，并应用于以下实际问题的模拟。-长通道中的气泡流动-复杂几何形状的两相流动-不同直径的二元液滴碰撞为了在计算中减少存储器的大小，将该方法发展为晶格动力学格式。晶格动力学方案有以下优点：计算中不需要速度分布函数，边界条件易于实现。该代码在并行机中实现，并应用于实际问题的模拟（气泡流，液滴碰撞，复杂通道中的两相流等）。

We first develop the numerical method for interfacial dynamics with large density differences by the lattice Boltzmann method. Next, the method is developed into the lattice kinetic scheme in order to reduce a memory size in computation. Finally, the code is implemented into a parallel machine and is applied to the simulations of practical problems.The summary in this study is as follows.1. The numerical method for interfacial dynamics with large density differences is developed.2. The method is applied to the simulations of binary droplet collisions and bubbly flows in order to investigate the followings.-the effect of the interfacial width on calculated results.-the effect of the mobility on calculated results.-the effect of the mesh size on calculated results.3. The code is implemented into a parallel machine and is applied to the simulations of the following practical problems.-bubbly flows in a long channel-two-phase flows in a complex geometry-binary droplet collisions with different diameters4. The method is developed into the lattice kinetic scheme in order to reduce a memory size in computation. The lattice kinetic scheme has the following advantages.-no need of the velocity distribution functions in computation-easy implementation of boundary conditions5. The code is implemented into a parallel machine and is applied to the simulations of practical problems (bubbly flows, droplet collisions, two-phase flows in a complex channel, etc).