在多介质大变形流动问题的数值模拟中，物质界面的精确追踪是非常重要的一个环节。本项目以多介质大变形流动为背景，在多介质ALE框架下，采用两条相连的线段来近似物质界面，改进界面模型，建立两线MOF界面重构方法。研究两线MOF方法的理论体系，研究两线MOF方法的高效最优化算法和并行算法，将两线MOF方法耦合到多介质ALE框架，应用于典型问题的数值模拟研究。本项目的研究有助于提高MOF界面重构的精度、分辨率和连续性，有助于提升多介质ALE计算的数值模拟精度和置信度，增强程序的健壮性，具有较为重要的理论研究意义和实际应用价值。

Exact interface tracking between two or more materials is one of the most important issues in numerical simulation of multi-material large deformation flows. In this proposal, we use two connected lines to approximate the material interface in mixed cell. Based on multi-materal arbitray Lagrangian-Eulerian (MMALE) framework, two lines moment-of-fluid (TL-MOF) interface reconstruction method is established and optimized. The theoretical system and highly efficient algorithms of TL-MOF are studied, the TL-MOF method is coupled with MMALE framework and applied to numercial simulation of typical problems. Using TL-MOF method, the accuracy, resolution and continuity of interface are improved significantly, the numerical performance and confidence of MMALE computing are advanced, the robustness of scientific computing programs is increased. This proposal is important in theoretical research and actual application for numercial simulation of multi-material large deformation flows.