Porous: Water Infiltration into a Concrete Block

Water Infiltration into a Porous Concrete Block

Description

This project simulates multiphase flow inside a porous cube using ANSYS Fluent. The main objective was to analyze the behavior of air and water within a porous medium using the Volume of Fluid (VOF) model. The simulation was carried out under transient, pressure-based conditions to observe how water interacts with air under a specified inlet pressure. The work proceeded through four main stages: geometry creation, meshing, solver setup, and post-processing to visualize the flow and pressure distributions.

Geometry and Mesh

The geometry was created in ANSYS Design Modeler as a cube measuring 0.15 m × 0.15 m × 0.15 m, with the inlet area defined as 0.0038472951 m². The geometry was then imported into ANSYS Meshing, where a structured hexahedral mesh of approximately 1 million elements was generated. This mesh type was chosen for its accuracy and numerical stability in capturing multiphase interactions, and it maintains adequate cell density near the boundaries, effectively representing the cube.

Methodology

The simulation was performed in ANSYS Fluent using a pressure-based, transient solver. The standard k–ε turbulence model was selected to account for turbulent effects. Multiphase flow was modeled with the Volume of Fluid (VOF) approach, with air defined as the primary phase and water as the secondary phase. A porous zone was included in the domain, with an assumed particle diameter (Dp) of 0.0005 m. The pressure inlet boundary condition was set to 500,000 Pa, driving water into the cube. The SIMPLE algorithm was applied for pressure-velocity coupling to ensure stability and convergence over the 15-second simulation period.

Conclusion

The results reveal the formation and interaction of the air and water phases within the cube over time. The VOF contours show the distribution of the water volume fraction, with water gradually rising through the porous region while displacing the air, and the air volume fraction plots highlight the interface separating the two phases. The velocity contours indicate that the maximum velocity occurs near the inlet region, while the upper portion of the cube remains largely stationary. The pressure distribution decreases gradually from the inlet toward the outlet, confirming the expected flow behavior through the porous medium. Overall, the simulation successfully demonstrates transient multiphase fluid interaction within a porous cube domain.