Model Tree

The model tree is where you determine the basic components for your model. Every model requires three absolutes: a simulation parameters component, a fluid configuration, and a main lattice component. By default, we add optional output planes. You can add more components to the model via the Create icon.

Model Tree Workflow

In M-Star CFD, the parent-child relationship is a foundational concept used to structure simulations. This hierarchical approach allows users to define global properties at the parent level and apply these properties to specific regions or geometries through child components.

Parents serve as containers for behaviors within a simulation. They define overarching characteristics such as:

  • Static and Moving Bodies: Global properties and boundary conditions assigned to a set of children.

  • Scalar Fields: Overall properties like diffusion coefficients, advection schemes, and scalar field densities.

  • Particles: Attributes including particle density, size distribution, forces, and interaction mechanics.

Importantly, parent components do not possess physical form until associated with child geometries. Parents therefore act as templates or blueprints, outlining how certain properties or behaviors should manifest within the simulation. New parents can be added to the model tree via the Create menu.

Children are representations defining where the properties defined by their parents are applied. They specify the shape, extent, and location within the simulation domain. For instance:

  • Geometry Definition: Defines the physical shape and extent of static boundaries, moving impellers, or regions where species are introduced.

  • Property Application: Determines where and how the parent’s properties—like scalar concentrations or particle injections—are applied within the simulation.

Children geometry can be added to parents by importing CAD files or selecting from geometry catalogs.

Existing parents and children (object families) can be duplicated, copied, and swapped between families using the Edit command. Parent and child geometry can be renamed by clicking the right mouse button.

Note

For particles and scalar parents, intermediate components may be nested within the parent-child hierarchy. These intermediate particle injection zones and scalar injection zones are used to customize the injection behavior of specific child geometry. When available, these child features can be added to the parents via context-specific tool bars.

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M-Star Pre contains the Model Tree and Property Grid.

Property Grid

The component that you select in the model tree will be reflected in the property grid. The properties of the parent are specified in the parent’s property grid. Likewise, the properties of the children and their geometry are defined in the childrens’ geometry grid.

  • Categories: These are sections within the property grid. Categories can be expanded by making certain selections.

  • Settings: These are subsections under the categories. Many settings contain combo boxes.

  • Selections & Parameters: These can be combo boxes, user-defined functions, or parameters. The available selections appear based on the settings you select.