This node adds several conditions for temperature exchange at the interfaces of an isothermal domain. It can be applied on interior and exterior boundaries of the computational domain, except on the boundaries found inside a single isothermal domain.
In addition to the default Isothermal domain Interface node always present when the
Isothermal domain check box is selected under
Physical Model section, you can add more
Isothermal domain Interface nodes if needed.
This section is available when temperature-dependent material properties are used. By default the temperature of the parent interface is used and the section is not editable. To edit the Temperature field, click
Make All Model Inputs Editable (
). The available options are
User defined (default),
Common model input (the
minput.T variable, set to 293.15 [K] by default) and all temperature variables from the physics interfaces included in the model. To edit the
minput.T variable, click the
Go to Source button (
), and in the
Common Model Inputs node under
Global Definitions, set a value for the
Temperature in the
Expression for remaining selection section.
If this node is selected from the Pairs menu, choose the pair on which to apply this condition. A pair has to be created first. See
Identity and Contact Pairs in the
COMSOL Multiphysics Reference Manual for more details.
The available Interface type options are
Thermal insulation (the default),
Continuity,
Ventilation,
Convective heat flux, and
Thermal contact. Depending on the
Interface type selected from the list, further settings are required.
The available Flow direction options are
Positive normal direction (the default),
Negative normal direction, and
Both sides. For each option, either the
Mass flux or the
Mass flow rate should be specified:
The External temperature found under the section of the same name must be set when the isothermal domain interface is also an exterior boundary.
When the Heat transfer coefficient h option is selected, the default option is to enter a
User defined value for the
Heat transfer coefficient h.
In addition, the following options are also available to control the type of convective heat flux to model: External natural convection,
Internal natural convection,
External forced convection, or
Internal forced convection. A complete description of these options can be found in
Heat Flux,
Convective Heat Flux.
The External temperature found under the section of the same name must be set when the isothermal domain interface is also an exterior boundary.
The External temperature found under the section of the same name must be set when the isothermal domain interface is also an exterior boundary.
This section is not available if the Interface type is set to
Thermal Insulation or
Continuity. Else, the
External temperature,
Text should be specified. It is used to compute the heat exchange with the exterior by the
Ventilation,
Convective heat flux, and
Thermal contact options on isothermal domain interfaces that are also exterior boundaries. The value is ignored on interior boundaries.
For User defined, enter a value or expression for the
Temperature Text. Else, select an
Ambient temperature defined in an
Ambient Thermal Properties node under
Definitions.
Select Opaque (the default) or
Transparent to set the interface’s opacity type.
If the Isothermal domain check box is selected under the
Physical Model section:
Heat Transfer>Isothermal Domain Interface
Heat Transfer in Solids>Isothermal Domain Interface
Heat Transfer in Fluids>Isothermal Domain Interface
Heat Transfer in Porous Media>Isothermal Domain Interface
Bioheat Transfer>Isothermal Domain Interface
is the mass flux in the positive direction and 
is the mass flux in the negative direction. 
