Flow path tortuosity in saturated porous media comprising idealised spherical particles

Extensive research has been conducted on tortuosity–porosity relationships for porous media. However, the relationship remains unclear, particularly when the porosity falls within the range 0·2–0·5, which covers most granular geomaterials. This study proposes a novel tortuosity–porosity model for estimating tortuosity in saturated porous media. Syringe tests were conducted by simulating seepage flow through a porous medium under Darcy’s law. The tortuosity was achieved after determining the porosity and permeability using the volumetric saturation method and constant-head method, respectively. Compared with existing models, the proposed model exhibited consistency at porosity values above 0·5 and improved smoothness as the porosity approached 0·2, which outperformed them in accurately predicting the tortuosities in these experiments. In addition, a sensitivity analysis against porosity demonstrated its precision, thereby facilitating its engineering application. These experimental results and model predictions provide valuable insights into the influence of pore geometry on flow paths and corresponding tortuosities.