Home
Setup
Prepare your model and run the simulation.
General Setup
Prepare your model for a general AcuSolve simulation.
Motion
Define direct, derived, and constrained mesh motion.
Derived Motion
Define how to interpolate the effect of the motion created with the Direct tools.
Define External Surface Motion
Use the External Surface tool to specify a fluid surface that interacts with a solid/structural surface from an external code in order to solve Direct Coupling Fluid Structure Interaction (DC-FSI) problems.

Welcome
What's New
View new features for HyperMesh CFD 2025.1.
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 Repair
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 thermal and solar radiation.
  - Motion
    Define direct, derived, and constrained mesh motion.
    - Set Up Mesh Motion
      Use the Settings tool to define the mesh motion equation to be solved.
    - Direct Motion
      Define explicit motion or motion sources on solids or surfaces.
    - Derived Motion
      Define how to interpolate the effect of the motion created with the Direct tools.
      - Define Interpolated Motion
        Use the Interpolated tool to interpolate direct mesh movement onto surrounding solids/surfaces and update the mesh accordingly.
      - Define External Surface Motion
        Use the External Surface tool to specify a fluid surface that interacts with a solid/structural surface from an external code in order to solve Direct Coupling Fluid Structure Interaction (DC-FSI) problems.
    - Constraints
      Define how the nodes will move around certain surfaces.
  - 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.
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.
Automation
Automate simulation processes with templates and utility scripts.
Solver Help
More resources for AcuSolve and ultraFluidX solvers.

View All Altair HyperWorks Help

Define External Surface Motion

Use the External Surface tool to specify a fluid surface that interacts with a solid/structural surface from an external code in order to solve Direct Coupling Fluid Structure Interaction (DC-FSI) problems.

Note: Before setting up an external surface, you need to enable external code in the Motion ribbon Settings tool. Based on the defined settings, relevant parameters will be exposed in the external surface microdialog.

From the Motion ribbon, click the External Surface tool.

Figure 1.
Select external code coupling surfaces.
Optional: If the entire domain moves as a rigid body, click Solids on the guide bar then select solids.
Define coupling parameters in the microdialog.
Relevant parameters are exposed based on your selections in the External code portion of the Settings tool.
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.