Fluid-Structure Interaction, Fixed Geometry
Use Fluid-Structure Interaction, Fixed Geometry () coupling when the deformations of the structure are so small that they do not significantly affect the fluid domain. Two effects can be modeled:
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The load from the fluid on the structure
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The structural velocity can act as a boundary condition on the fluid.
Settings
The Label is the default multiphysics coupling feature name.
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 fsifg1.
Coupling Type
Select Fully coupled (the default), Fluid loading on structure, or Velocity transmission to fluid.
Fluid-Structure Interaction, Fixed Geometry
This section defines the physics interfaces involved in the Fluid-Structure Interaction, Fixed Geometry coupling. The Fluid flow and Solid mechanics 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 (Mac 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 Fluid-Structure Interaction, Fixed Geometry node from a physics interface. If the physics interface is removed from the Model Builder, for example Solid Mechanics is deleted, then the Solid mechanics 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 re-establish 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 Approaches in the COMSOL Multiphysics Reference Manual.