porousMultiphaseFoam v2107: An open-source tool for modeling saturated/unsaturated water flows and solute transfers at watershed scale

The first releases of porousMultiphaseFoam proposed an open-source software suite to solve the equations for multiphase flow (generalized Darcy’s law) in porous media or groundwater flows (Richards' equation) by taking advantage of OpenFOAM, a finite volume platform with automatic discretization on three-dimensional unstructured grids and good parallel efficiency. Recently, the porousMultiphaseFoam toolbox has been confronted with complex cases of fast water flows and solute transfers in realistic hydrological configurations with variable forcing conditions (heterogeneous infiltration and local tracer injection). Several developments have been carried out to make it possible to simulate those cases, which extend the toolbox with: (i) a set of solvers dedicated to groundwater flows, including coupled water flow and solute transport and simplified 2D approaches, (ii) improved numerical techniques for problems with strong non-linearities, (iii) libraries/executables for pre-processing of input data (geographical information and time-variable forcing terms) and (iv) passive or coupled scalar transport (tracer) with groundwater solvers that support any number of species. New solvers are validated on several (un-)saturated configurations by a direct comparison with a well validated finite element code.

初期版本的多孔多相泡沫软件套件提出了一个开源解决方案，以利用OpenFOAM这一基于有限体积法的平台，在三维非结构化网格上实现自动离散化，并具备出色的并行效率，来求解多孔介质或地下水流动（理查兹方程）中的多相流动方程（广义达西定律）。近期，面对现实水文配置中快速水流和溶质转移的复杂案例，以及可变强迫条件（异质渗透和局部示踪剂注入），porousMultiphaseFoam工具箱遭遇了挑战。为模拟这些案例，已进行数项开发工作，拓展了工具箱的功能，包括：(i) 专为地下水流动设计的求解器集，涵盖了耦合水流和溶质迁移以及简化的二维方法，(ii) 针对强非线性问题的改进数值技术，(iii) 输入数据处理（地理信息和时间可变强迫项）的库/可执行文件，以及(iv) 与支持任意物种数量的地下水求解器相结合的被动或耦合标量传输（示踪剂）。新求解器通过直接与经过充分验证的有限元代码进行比较，在多个（非）饱和配置上得到了验证。