This node is the default edge condition on shells. This condition means that there is no heat flux across the edge:

and hence specifies where the shell is insulated. In most cases, the heat flux q is defined from the Fourier’s law, and this condition sets the temperature gradient to zero across the edge. As the default edge condition, this feature is applicable only on external edges; but when added manually, it can be applied on interior edges as well.

At internal edges, and as a subfeature of Thin Layer, Thin Film or Fracture features, the thermal insulation condition can always be applied, but is only taken into account when the Layer type is General in the parent feature.

At internal edges corresponding to the junction of shells of different layered materials, if the Layer type is General in the Thin Layer, Thin Film or Fracture parent feature (Heat Transfer interface), or in the Solid, Fluid, or Porous Medium feature (Heat Transfer in Shells interface), thermal insulation is implicit, and the temperature field is discontinuous across the edge, even if no Thermal Insulation subnode is active. This default behavior can be modified by using the Shell Continuity (Heat Transfer Interface) and Continuity (Heat Transfer in Shells Interface) feature on the edge.

Select the edges on which to apply a no flux condition. The Restrict to layered edges check box makes the node applicable only if a layered material is defined on the edge. If a layered material (Material with Layer thickness specified, Single Layer Material, Layered Material Link, or Layered Material Stack) is available, its name is then displayed beside the edge index (for example, slmat1), otherwise the edge is marked as not applicable.

Note that when the Shell type is Nonlayered shell in the Shells Properties section of the parent interface or node, the Restrict to layered boundaries check box is not editable.

In addition, in 2D, edges are modeled as points and this section is named Point Selection, containing a Restrict to layered points check box.

This section is available only when the Shell type is Layered shell in the Shells Properties section of the parent interface or node. You can limit the contribution to individually selected layers by clearing the Use all layers check box. For a given Layered Material Link or Layered Material Stack, you get access to a list of check boxes for the selection of the individual layers.

Physics tab with Thin Layer selected in the model tree:

Physics tab with Heat Transfer in Shells selected: