Fluid Properties

The node adds the momentum and continuity equations solved by the physics interface. For the viscoelastic fluids, the constitutive relations for the extra elastic stress tensor are also added. The node also provides an interface for defining the material properties of the fluid.

Except where included below, see Fluid Properties for all the other settings.

Viscoelastic, Newtonian and Inelastic non-Newtonian constitutive relations are available. If constitutive relation is selected, the node also adds the variables and equations for the components of the elastic stress tensor.

For constitutive relation, specify μs and select a — , , , , or . Viscoelastic material can be described as consisting of one or more branches. For each viscoelastic branch, enter parameters in the table. See the setting for each viscoelastic model that follows.

For enter the model parameters in the table. In each raw enter the polymer viscosity

in the column, and the relaxation time

in the column.

For , in each raw enter the polymer viscosity

in the column, the relaxation time

in the column, and the mobility factor

in the column.

For , in each raw enter the polymer viscosity

in the column, the relaxation time

in the column, and the extensibility parameter

in the column.

For ,in each raw enter the polymer viscosity

in the column, the relaxation time

in the column, and the extensibility

in the column.

For ,in each raw enter the polymer viscosity

in the column, the relaxation time

in the column, and the extensibility

in the column.

•

Use the button (

) to add a row to the table and the button (

) to delete a row in the table.

•

Use the button (

) and the button (

) to load and store data for the branches in a text file with three space-separated columns.

To display this section, click the button (

) and select in the dialog box. Select shape function type for the components of the auxiliary viscoelastic tensor. The default setting is .

To display this section, click the button (

) and select in the dialog box. Enter initial values or expressions for the components of the auxiliary viscoelastic tensor. The initial values can serve as an initial condition for a transient simulation or as an initial guess for a nonlinear solver. The default values are 0 N/m2. Note, that if several branches are specified, the initial values entered above are applied to all branches.

The boundary condition and Pair conditions are not applicable on the boundaries that are adjacent to the Fluid properties nodes with different number of branches.