Author(s): Tomoki Izumi; Naoyuki Yamashita

Linked Author(s): Tomoki Izumi

Keywords: Non-Darcy flow; Particle method; Numerical simulation; Seepage experiment

Abstract: Water movement through porous media is generally governed by Darcy's law. However, it has been indicated that flow under high Reynolds numbers, such as flow through coarse porous media under a high hydraulic gradient, does not always satisfy Darcy's law. Such flow is known as non-Darcy flow, and Forchheimer’s and Izbash’s law have been proposed as the momentum equation. In this study, numerical models for non-Darcy flow based on each law are developed. The governing equation is composed of a continuity equation and a momentum equation, the Navier−Stokes equation with an additional non-linear resistance term based on Forchheimer's or Izbash’s law instead of Darcy's law. The governing equation is also discretized using the Moving Particle Simulation (MPS) method. The MPS method is one of the fully Lagrangian particle methods and discretizes differential operators, such as gradient and Laplacian, based on the particle interaction models. Physical and numerical experiments for seepage phenomena in coarse porous media are implemented to investigate the model validity and compare computational results from two numerical models. Three kinds of soil materials of gravel with 1.4cm of 50% grain size, gravel with 0.8cm of 50% grain size, and glass beads with 0.5cm of 50% grain size are used and at most six kinds of water level difference are imposed for each soil material in the experiments. The results of the experiments indicate that the model based on Izbash’s law would be slightly more suitable for flow through coarser porous media than the model based on Forchheimer’s law.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221380

Year: 2022