# Custom zones

Custom zones allow you to create user-defined volume mesh zones from custom volumes. The names of the generated volume zones will match the names of the custom volumes.

# Available Options

Option Description Applicable
Name Name of the custom zone setting always
Element type Type of mesh elements to use in the zone always
Assigned custom volume Custom volume entities to generate zones from always

# Detailed Descriptions

# Name

Display name for this custom zone configuration.

  • Default: Custom zone

# Element type

Specifies the type of mesh elements to be used for the generated volume zones.

Possible selections:

  • Mixed - Tetrahedral and tet elements in the mesh volume

  • Tetrahedra - Only tetrahedral elements will be used for the generated volume zones

  • Default: Mixed

Notes:

  • Mixed typically produces fewer elements and better quality for most geometries
  • Tetrahedra may be preferred for CHT solid zones

# Assigned custom volume

The custom volume entities from which volume zones will be generated.

  • Required

Notes:

  • Select volumes from the 3D scene or from the entity list using the + button
  • Each custom volume will generate a separate volume zone with the same name
  • Volume zone names must be unique across the simulation

💡 Tips
  • Use custom zones to define regions where you need specific volume zone properties (e.g., for porous media or user-defined expressions)
  • Ensure custom volume names are descriptive as they become the volume zone names in the solver

❓ Frequently Asked Questions

  • When should I use Mixed vs Tetrahedra element type?

    Use Mixed (default) for most cases as it produces better quality meshes with fewer elements. Use Tetrahedra need an all-tet mesh, for example for Solid zones.

  • Can I have multiple custom zones?

    Yes, you can define multiple custom zone configurations, each with different custom volumes and element types.

🐍 Python Example Usage

 
import flow360 as fl

# Define a custom volume entity
custom_volume = fl.CustomVolume(
    name="WakeRegion",
    # ... volume definition
)

# Create custom zones
custom_zones = fl.CustomZones(
    name="Custom zones",
    entities=[custom_volume],
    element_type="mixed"
)

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