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Setup
Prepare your model and run the simulation.
General Setup
Prepare your model for a general AcuSolve simulation.
Radiation
Define radiation conditions and create emissivity models.
Participating Media
Define participating media radiation conditions.
Define Participating Media External Boundaries
Use the External Boundary tool to define diffusion and refractive properties of wall surfaces of participating media.

Welcome
What's New
View new features for HyperMesh CFD 2024.1.
Get Started
Learn the basics and discover the workspace.
Onboarding Resources
Discover HyperMesh CFD functionality with interactive tutorials and community resources.
Solution Layers
Solution-centric workflows allow you to traverse through modeling environments using a dedicated UI layer.
Manage Files and Data
Create, open, import, and save models.
Convert
Use the Convert tool to convert entire models between data types.
Geometry Modeling
Manage CAD, FE, and 2D parametric sketch geometry.
Meshing
Generate surface/volume mesh by defining mesh controls, or interactively create and edit 2D surface mesh.
Setup
Prepare your model and run the simulation.
- General Setup
  Prepare your model for a general AcuSolve simulation.
  - Flow
    Set up the simulation model, materials, domains, and boundaries.
  - Radiation
    Define radiation conditions and create emissivity models.
    - Thermal Radiation
      Define thermal radiation conditions.
    - Participating Media
      Define participating media radiation conditions.
      - Define Participating Media Models
        Use the Model tool to create, delete, and import/export participating media models.
      - Assign Participating Media
        Use the Assign tool to apply participating media properties to selected solids. Solids which are not assigned any participating media model are considered as non-participating.
      - Define Participating Media Interface Surfaces
        Use the Interface tool to define diffusion properties of interface surfaces across participating media.
      - Define Participating Media External Boundaries
        Use the External Boundary tool to define diffusion and refractive properties of wall surfaces of participating media.
    - Solar Radiation
      Define solar radiation conditions.
  - Motion
    Define direct, derived, and constrained mesh motion.
  - Solution
    Define output conditions, run the simulation, and view the results.
  - AcuTrace
    AcuTrace is particle tracer that runs as a post-processor to AcuSolve.
- Aerodynamic and Aeroacoustic Setup
  Prepare your model for wind tunnel analysis using ultraFluidX.
Post-Processing
Post-process the simulation results by creating visualizations and measurements.
Automation
Automate simulation processes with templates and utility scripts.
Design Exploration
Once the baseline model is prepared, you can define morph volumes, morph geometry, create design shapes and run DOE studies. These tool work for both AcuSolve and ultraFluidX-based workflows.
Solver Help
More resources for AcuSolve and ultraFluidX solvers.

View All Altair HyperWorks Help

Define Participating Media External Boundaries

Use the External Boundary tool to define diffusion and refractive properties of wall surfaces of participating media.

From the Radiation ribbon, click the External Boundary tool.

Figure 1.
Select interface surfaces between participating media model solids and external environments.
- You can only select wall surfaces of participating media solids which are exposed to external environments (not connected to other participating or non-participating media).
- If the physics model is not set to P1 or DO, you will not be allowed to select any surfaces.
- If interface surfaces are not selected, they will be automatically assigned with the default properties set in the Thermal Radiation Physics tool.
In the microdialog, define the diffused fraction, specular ordinate averaging method, refractive index, and external temperature.
From the guide bar, execute the command in the following ways:
- Click to confirm your selection and remain in the tool.
  This allows you to continue creating instances and helps you visualize and edit instances with the legend.
- Click to confirm your selection and exit the tool.