The Fluid and Matrix Properties node adds the Brinkman equations: Equation 7-5 and Equation 7-6 (excluding any mass sources), and provides an interface for defining the properties of the fluid material and the porous matrix The Forchheimer Drag subnode is available from the context menu (right-click the parent node) or from the Physics toolbar, Attributes menu.

The default Fluid material uses the Domain material (the material defined for the domain). Select another material as needed.

Both the default Density ρ (SI unit: kg/m3) and Dynamic viscosity μ (SI unit: Pa·s) use values From material based on the Fluid material selection. For User defined enter another value or expression. In this case, the default is 0 kg/m3 for the density and 0 Pa·s for the dynamic viscosity. The dynamic viscosity describes the relationship between the shear stresses and the shear rate in a fluid. Intuitively, water and air have a low viscosity, and substances often described as thick, such as oil, have a higher viscosity. Non-Newtonian fluids have a viscosity that is shear-rate dependent. Examples of non-Newtonian fluids include yogurt, paper pulp, and polymer suspensions.

The default Porous material uses the Domain material (the material defined for the domain) for the porous matrix. Select another material as needed.

Both the default Porosity εp (a dimensionless number between 0 and 1) and Permeability κ (SI unit: m2) use values From material as defined by the Porous material selection. For User defined select Isotropic, Diagonal, Symmetric, or Anisotropic based on the characteristics of the permeability, and enter another value or expression. The components of a permeability in the case that it is a tensor (κxx, κyy, and so on, representing an anisotropic permeability) are available as br.kappaxx, br.kappayy, and so on (using the default name br).