# Rotation regions

A set of Rotation cylinders. A rotation cylinder volume zone is designed specifically for regions containing rotating components. It ensures proper mesh refinement and enables accurate simulation of rotating machinery.

# Configuration Parameters

Parameter Description
Spacing axial Mesh spacing along the cylinder's axis
Spacing radial Mesh spacing in the radial direction
Spacing circumferential Mesh spacing around the circumference
Assigned cylinders Cylindrical components to which this zone applies
Enclosed entities Additional geometric entities within the cylinder

# Detailed Descriptions

# Spacing Axial

Defines the mesh spacing along the cylinder axis.

  • Required
  • Example: 0.02 m

Note: Critical for capturing axial flow features and gradients.

# Spacing Radial

Specifies the mesh spacing in the radial direction.

  • Required
  • Example: 0.01 m

Note: Important for resolving radial flow patterns and boundary layer development.

# Spacing Circumferential

Controls the mesh spacing in the circumferential direction.

  • Required
  • Example: 0.015 m

Note: Essential for capturing rotational effects and circumferential variations.

# Assigned cylinders

Identifies the cylindrical regions where axisymmetric refinement will be applied.

  • Required

Notes:

  • Must reference valid cylinder entities in the geometry.
  • Assign the cylinders by selecting from the list using the + button or select graphically in the viewer region.

# Enclosed entities

The bodies that the rotation region encloses.

  • Default: None

Notes:

  • Assign the entities by selecting from the list using the + button or select graphically in the viewer region.
  • Body walls cannot intersect with the walls of the rotation cylinder.

# Key Features

  • Generates concentric mesh structure ideal for rotating components
  • Can enclose other objects without intersecting them
  • Supports donut-shaped configurations for stationary centerbody placement
  • Compatible with Flow360's Rotation model

💡 Tips
  • Match spacing values to the expected flow features:
    • Use finer axial spacing in regions of strong axial gradients
    • Ensure adequate radial spacing for boundary layer resolution
    • Consider tip vortex resolution when setting circumferential spacing
  • Keep computational efficiency in mind when setting spacing values
  • Verify that assigned cylinders are properly aligned with rotation axes
  • Ensure enclosed entities are fully contained within the rotation cylinder

❓ Frequently Asked Questions

  • What spacing values should I use for rotation cylinders?

    The spacing values depend on your specific case, but should be fine enough to capture boundary layers and wake effects around rotating components while considering computational resources.

  • Can I have multiple rotation cylinders?

    Yes, you can define multiple rotation cylinder zones with different spacing parameters for different components.

🐍 Python Example Usage

Below is a Python code example showing how to configure rotation regions using the Flow360 Python API:

import flow360 as fl
from flow360 import u

# Example 1: Basic rotation cylinder configuration
rotation_zone = fl.RotationCylinder(
    spacing_axial=0.02 * u.m,
    spacing_circumferential=0.015 * u.m,
    spacing_radial=0.01 * u.m,
    entities=cylinder  # Reference to cylinder geometry entity
)

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