Shell–Thin-Film Flow Interaction
The Shell–Thin-Film Flow Interaction () multiphysics node provides a coupling on a boundary between a thin fluid film and a shell.
The Shell–Thin-Film Flow Interaction node is only available with some COMSOL products (see https://www.comsol.com/products/specifications/).
Settings
The Label is the multiphysics coupling feature name. The default Label (for the first multiphysics coupling feature in the model) is Shell–Thin-Film Flow Interaction 1.
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 in the model) is shtfi1.
Boundary Selection
By default, the selection is set to All boundaries. However, only boundaries between fluid and solid domains are applicable. This is deduced automatically using the selections made on the coupled physics interfaces.
Coupled Interfaces
This section defines the physics interfaces involved in the Structure Thin-Film Flow Interaction coupling. The Structure and the Thin film lists include all applicable physics interfaces.
The default values depend on how the node is created.
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If it is added from the Physics ribbon (Windows users), Physics contextual toolbar (macOS and Linux users), or context menu (all users), then the first physics interface of each type in the component is selected as the default.
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If it is added automatically when the physics interface is chosen in the Model Wizard or Add Physics window, then the two participating physics interfaces are selected.
You can also select None from either list to uncouple the Shell–Thin-Film Flow Interaction node from a physics interface. If the physics interface is removed from the Model Builder, for example Shell is deleted, then the Structure list defaults to None as there is nothing to couple to.
If a physics interface is deleted and then added to the model again, then in order to reestablish the coupling, you need to choose the physics interface again from the lists. This is applicable to all multiphysics coupling nodes that would normally default to the once present physics interface. See Multiphysics Modeling Workflow in the COMSOL Multiphysics Reference Manual.
Film Location
In this section, you specify the load contributions that are transferred from the Thin-Film Flow interface to the Shell interface.
Select Top to include the load from the fluid on the top side of the shell.
Select Bottom to include the load from the fluid on the bottom side of the shell.