Isothermal Domain
This node should be used when the temperature shows sufficiently small spatial fluctuations to be considered homogeneous in space but not necessarily in time.
Model Input
This section has fields and values that are inputs to expressions that define material properties. If such user-defined property groups are added, the model inputs appear here.
Temperature
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.
Isothermal Domain
Two options are available for the Temperature definition into the Isothermal Domain:
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If From heat balance (the default) is selected, the temperature is computed as the solution of a reduced form of the heat equation due to spatial homogeneity. See Equation 4-32.
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If From prescribed temperature is selected, the temperature is set to the domain Temperature T0 that needs to be specified. For User defined, enter a value or expression for the Temperature T0. Else, select an Ambient temperature defined in an Ambient Thermal Properties node under Definitions.
Thermodynamics
The thermodynamics properties of the Isothermal Domain are set in this section. Two options are available for the Mass definition:
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If Density is selected, the Density ρ should be specified.
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If Total mass is selected, the Mass m should be specified.
Finally the Heat capacity at constant pressure Cp should be specified.
It is not possible to couple an Isothermal Domain with the Laminar Flow interface through the Nonisothermal Flow multiphysics condition.
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The following conditions of heat exchange can be applied at isothermal domain interfaces: thermal insulation, continuity, ventilation, convective heat flux, and thermal contact. See Isothermal Domain Interface for more details.
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Also see Theory for Lumped Isothermal Domain.
When Surface-to-surface radiation is activated, the Opacity (Surface-to-Surface Radiation interface) subnode is automatically added to the entire selection, with Transparent option selected. The domain selection can’t be edited. To set some part of the domain as opaque, add a new Opacity (Surface-to-Surface Radiation interface) subnode from the context menu (right-click the parent node) or from the Physics toolbar, Attributes menu.
Natural Convection Cooling of a Vacuum Flask: Application Library path Heat_Transfer_Module/Tutorials,_Forced_and_Natural_Convection/vacuum_flask
Location in User Interface
Context menus
If the Isothermal domain check box is selected under the Physical Model section:
Heat Transfer>Isothermal Domain
Heat Transfer in Solids>Isothermal Domain
Heat Transfer in Fluids>Isothermal Domain
Heat Transfer in Porous Media>Isothermal Domain
Heat Transfer in Building Materials>Isothermal Domain
Bioheat Transfer>Isothermal Domain
Ribbon
Physics Tab with interface as Heat Transfer, Heat Transfer in Solids, Heat Transfer in Fluids, Heat Transfer in Porous Media, Heat Transfer in Building Materials or Bioheat Transfer selected:
Domains>interface>Isothermal Domain