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. Each assigned custom volume, and every surface the fluid zone encloses, must also be listed in the farfield’s Enclosed entities.

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

See also

For a deeper discussion of the meshing workflow and parameters, see Meshing.

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

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❓ 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 when you need an all-tet mesh, for example for CHT solid zones.

• Can I have multiple custom zones?

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

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🐍 Python Example Usage

See also

Python API:

• CustomVolume

• CustomZones

Example Library notebooks:

• Conjugate Heat Transfer

import flow360 as fl

project = fl.Project.from_cloud(project_id="prj-XXXXX")  # Should be a valid project id
geometry = project.geometry

# Define a custom volume from the surfaces that bound it.
# The bounding entities are the surfaces enclosing the region (e.g. interfaces
# selected from the geometry). The generated volume zone takes the
# custom volume's name.
wake_region = fl.CustomVolume(
    name="WakeRegion",
    bounding_entities=[
        geometry["wake_interface_inlet"],
        geometry["wake_interface_outlet"],
    ],
)

# Create the custom zone(s) from one or more custom volumes.
custom_zones = fl.CustomZones(
    name="Custom zones",
    entities=[wake_region],
    element_type="mixed",  # or "tetrahedra" for an all-tet zone
)