Right-click a Porous Material node to add a Immobile Fluid subnode () to define properties of an immobile fluid phase in the porous medium.

From the Material list, choose the material to represent the immobile fluid: Locally defined (the default), or select any other material that you have added. Click the Go to Material button () to move to the selected material’s node. Click the Add Material from Library button ( to add a material from the Add Material to Pellet window. You can also click the downward arrow next to the button and choose Blank Material to add a new blank material. In both cases, the added material becomes selected in the Material list.

For the immobile fluid’s Volume fraction, enter a value between 0 and 1 in the θimf field.

This section is only available if you have selected Locally defined from the Material list in the Immobile Fluid Properties section. You can then choose material properties that you want to add for the immobile fluid from the list and then click the Add to Material button () to add those properties to the table in the Material Contents section below.

This section contains a table with the material properties for the immobile fluid, which typically consist of the porosity and the material properties from the chosen material for the immobile fluid. When the Material in the Immobile Fluid Properties section is Locally defined, enter values or expressions for the properties in the Value column. You can also click the Edit button () below the table to enter the property values.