Overriding Mechanism for Heat Transfer Boundary Conditions
Many boundary conditions are available in heat transfer. Some of these can coexist (for example, Heat Flux and Thin Layer (Heat Transfer interface) and Solid (Heat Transfer in Shells interface)); others cannot (for example, Heat Flux and Thermal Insulation).
Several categories of boundary condition exist in heat transfer. Table 3-3 gives the overriding rules for these groups.
1
2
3
4
5
6
When there is a boundary condition A above a boundary condition B in the model tree and both conditions apply to the same boundary, use Table 3-3 to determine if A is overridden by B or not:
Locate the line that corresponds to the A group (see above the definition of the groups). In the table above only the first member of the group is displayed.
If the corresponding cell is empty, A and B contribute. If it contains an X, B overrides A.
Example
Consider a boundary where Heat Flux is applied. Then a Symmetry boundary condition is applied on the same boundary afterward.
Heat Flux belongs to group 3.
Symmetry belongs to group 2.
This mechanism can be checked on the COMSOL Desktop, in the Override and Contribution section of each feature, as shown in the following table:
Table 3-4: Override and Contribution sections
In the example above, if Symmetry followed by Heat Flux is added, the boundary conditions contribute.