Diffusion-compaction_coupling_Data_and_postprocessing_codes

This repository contains the data, simulation outputs, and analysis code accompanying a paper on pore pressure feedback in granular beds — specifically fluidized/aerated particle beds relevant to geophysical and industrial flows. The work models 1D porous media flow with compaction, excess pore pressure diffusion, and dynamic permeability. The repository is organized by figure, with each folder containing raw simulation data (CSV outputs from MFiX), a Jupyter notebook to reproduce the plot, and the resulting PDF figure: Figure 1 — Permeability analysis at minimum fluidization velocity (Umf), comparing simulations to theory. Figure 2 — Validation of a custom 1D excess pressure solver (with/without compaction source term) against MFiX numerical simulations. Figure 3 — Four-panel decomposition of pressure contributions across varying bed heights. Figure 4 — Fourier mode convergence study for the analytical/semi-analytical solution. Figure 5 — How initial and final packing fractions (ε) vary with bed height H. Figure 6 — Comparison of an algebraic model for the fluidization parameter ψ against full simulations. Figures 7–11 — IMEX (implicit-explicit) solver results, including dam-break implementations inspired by Aravena (2021) and grid-search parameter studies with dynamic permeability. Figure 12 — Maps of fitted diffusivity (D_fit), predicted diffusivity (D_pred), and ψ₀ for air, exploring parameter space. The codebase uses Python (NumPy, Numba) for solvers and Jupyter notebooks for visualization, with MFiX providing reference Two-Fluid Method (TFM) simulation data.本仓库包含与一篇关于颗粒床孔隙压力反馈的论文配套的数据、模拟结果与分析代码——该研究聚焦于与地球物理及工业流动相关的流化/充气颗粒床。该项工作构建了考虑压实效应、超孔隙压力扩散与动态渗透率的一维多孔介质流动模型。 本仓库按插图编号进行分类，每个文件夹均包含原始模拟数据（来自MFiX的CSV格式输出文件）、用于复现对应绘图的Jupyter Notebook，以及最终生成的PDF格式插图： 图1 — 最小流化速度（minimum fluidization velocity, Umf）下的渗透率分析，将模拟结果与理论模型进行对比。 图2 — 自定义一维超压求解器（考虑/不考虑压实源项）的验证结果，与MFiX数值模拟结果对标。 图3 — 不同床层高度下压力贡献的四分区分解示意图。 图4 — 解析/半解析解的傅里叶模态收敛性研究。 图5 — 初始与最终充填率（packing fractions, ε）随床层高度H的变化规律。 图6 — 流化参数（fluidization parameter, ψ）的代数模型与完整模拟结果的对比。 图7至图11 — 隐式-显式（implicit-explicit, IMEX）求解器的结果，包括受Aravena(2021)研究启发的溃坝模拟实现，以及带有动态渗透率的网格搜索参数研究。 图12 — 针对空气的拟合扩散系数（fitted diffusivity, D_fit）、预测扩散系数（predicted diffusivity, D_pred）与ψ₀的参数空间映射图。 本代码库使用Python（依托NumPy、Numba库）实现求解器，并通过Jupyter Notebook完成可视化，其中MFiX用于提供双流体模型（Two-Fluid Method, TFM）的参考模拟数据。