有界压缩VOF算法在界面流问题中的应用

Application of bounded and compressed VOF method to interfacial flow

通过在界面标识方程中引入人工压缩项,采用基于非结构网格的高分辨率有界格式,编程实现了一类适合模拟复杂界面流问题的VOF(Volume of Fluid)方法.这类VOF方法可以自动处理界面的拓扑演化,无须进行实时的界面重构,提高了计算效率.应用这种基于有界压缩思想的界面流模拟方法,对三维Rayleigh-Taylor不稳定性问题进行了并行模拟.计算结果与相关文献的数据吻合较好,证明了算法的可靠性.研究了密度差和Reynolds数对界面演化的影响,分析了在不同Atwood数下鞍点结构演化规律的异同,对于Reynolds数小于282的界面流问题黏性起着很明显的作用,而Atwood数的影响限于低密度差的界面流动问题,即Atwood数小于0.90的情形.

A kind of volume of fluid （VOF） method was developed based on the combination of a novel marker equation with artificial compression and a high resolution normalized variable diagram （NVD） differencing scheme for arbitrarily unstructured meshes. The VOF method was designed specially for the simulation of complicated interracial flow problem. The topological changes of interface were automatically handled in this VOF method and no interface reconstruction procedure needed. Three-dimensional Rayleigh-Taylor problem was solved with the presented VOF method and good agreements with the available benchmark data were achieved. The evolution of saddle-point structures with varied Atwood number was analyzed. When the Reynolds number less than 282, the viscosity significantly decides the interface topology, while when the Atwood number less than 0.90, the density is important.