Introduction To Porosity

Porosity Introduction

A porous medium is a material in which all the volume is not solid and has void holes. However, if this medium is in front of the motion of the fluid, the fluid can pass through the cavities. The application of porous media in simplifying various CFD simulations is significant. As it turns out, the pressure drop of a fluid when it passes through a porous medium is greater than the absence of a porous medium. Therefore, to simulate a porous medium, we can see the effects of pressure drop with a negative pressure source term.

Pressure drop in a porous medium

Pressure drop in porous medium has two types:

1. Viscous resistance
2. Inertial resistance

Viscous resistance is related to friction pressure drops caused by fluid viscosity, which is important in laminar flow regimes. The inertial resistance is related to the fluid dynamic head drop. In the turbulent flow regime, the inertial resistance effect on pressure drop is greater than the viscous resistance.

Heterogeneous porous medium

We may have a porous medium in which the viscous and inertial resistance pressure drops are not the same in different directions due to the anisotropy of the porosity. ANSYS Fluent software gives us the ability to define viscous and inertial resistance separately, in three directions of X, Y, and Z (for two-dimensional geometries in two directions of X and Y).

Here is one of the related practical exercises that existed in Learning Products:

ACSC Performance with Diffuser Orifice Plate, Paper Numerical Validation, ANSYS Fluent Tutorial