The Two-Phase Thin-Film Flow, Phase Field (
) interface contains a multiphysics coupling feature,
Two-Phase Thin-Film Flow, Phase Field, which is added automatically.
The Two-Phase Thin-Film Flow, Phase Field multiphysics coupling feature defines the density and dynamic viscosity of the fluid used in the
Thin-Film Flow interface, and it defines the surface tension on the interface in form of a volume force used in the momentum equation. It also enables the
Phase Field interface or the
Phase Field, Thin-Film Flow interface to use the velocity field calculated from the
Thin-Film Flow interface to transport the interface.
The Label is the default multiphysics coupling feature name.
The Name is used primarily as a scope prefix for variables defined by the coupling node. Refer to such variables in expressions using the pattern
<name>.<variable_name>. In order to distinguish between variables belonging to different coupling nodes or physics interfaces, the
name string must be unique. Only letters, numbers, and underscores (_) are permitted in the
Name field. The first character must be a letter.
The default Name (for the first multiphysics coupling feature
Two-Phase Thin-Film Flow, Phase Field in the model) is
tpf1.
When nodes are added from the context menu, you can select All domains (the default) or select
Manual from the
Selection list to choose specific domains.
By default, the Temperature model input is set to
Common model input, and the temperature is controlled from
Default Model Inputs under
Global Definitions or by a locally defined
Model Input. If a Heat Transfer interface is included in the component, it controls the temperature
Common model input. Alternatively, the temperature field can be selected from another physics interface. All physics interfaces have their own tags (
Name). For example, if a Heat Transfer in Fluids interface is included in the component, the
Temperature (ht) option is available for
T.
You can also select User defined from the
Temperature model input in order to manually prescribe
T.
To specify the properties of Fluid 1 from a material, select the appropriate material in the
Fluid 1 list. Also make sure that the
Density of fluid 1,
ρ1, and
Dynamic viscosity of fluid 1,
μ1, are both set to
From Material.
To instead apply a variable or expression for the density or dynamic viscosity for Fluid A, select User defined in the
Density of fluid 1,
ρ1, or the
Dynamic viscosity of fluid 1,
μ1, list and enter the expression in the corresponding text field.
Similarly, the properties of Fluid 2 can be specified. The default material is set to
None.
The default method for Density averaging and
Viscosity averaging is
Volume average. In addition to the default method,
Density averaging can be set to
Heaviside function or
Harmonic volume average, while
Viscosity averaging can be set to
Heaviside function,
Harmonic volume average,
Mass average, or
Harmonic mass average. When a
Heaviside function is used, enter a value for the corresponding mixing parameter,
lρ or
lμ.
The specification of the Density averaging is not available when the Modified Reynolds Equation option is chosen in the
Thin-Film Flow interface.
Select the Include surface tension force in momentum equation check box to include the surface tension force in the momentum equation. Select a
Surface tension coefficient σ (SI unit: N/m):