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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.
Setup
Define global simulation settings, materials, and any multipliers or parameters.
Physics Setup Workflows
An overview of how to set up various simulation scenarios.
Set Up Compressible Flow Modeling

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.
    - Setup
      Define global simulation settings, materials, and any multipliers or parameters.
      - Set Up the Simulation Model
        Use the Physics tool to define the global AcuSolve settings used in the simulation.
      - Physics Setup Workflows
        An overview of how to set up various simulation scenarios.
        Set Up Immiscible Multiphase Modeling
        Set Up Disperse Multiphase Modeling
        Set Up Eulerian and Granular Multiphase Modeling
        Set Up Compressible Flow Modeling
        Set Up Humidity Modeling
        Set Up Species Transport Modeling
        Set Up Contact Angle Modeling
        Set Up EDEM Coupling
      - Define Materials
        Use the Material Library tool to create, edit, delete, and import/export fluid, solid, or immiscible multiphase materials. Once defined, these materials can be referenced in any domain.
      - Define Parameters
        Use the Parameters tool to create, delete, and import/export parameters.
      - Define Multiplier Functions
        Use the Multipliers tool to create, edit, and delete multiplier functions. Multiplier or ramp functions are used to multiply or ramp variables while defining boundaries, radiation, and mesh conditions.
    - Domain
      Define the simulation domain.
    - Boundaries
      Define surface boundary conditions.
  - Radiation
    Define thermal and solar radiation.
  - 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.
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

Set Up Compressible Flow Modeling

Simulate high speed flows with speeds ranging from subsonic to transonic up through low supersonic conditions. Compressible flow simulations should be conducted using a transient analysis with ideal gas properties for air. AcuSolve will compute the coupled system of compressible NS equations with a single non-linear iteration using the "compressible_flow" stagger. Compressible flow is compatible with the supported turbulence models and most other existing AcuSolve features

From the Flow ribbon, click the Physics tool.

Figure 1.
Under the Physics models settings, set the flow radio buttons to Single phase and Supersonic.
Select an ideal gas model or open the Material Library to create and edit material models.
Use the Material tool on the Flow ribbon to assign the ideal gas material to the solid body.
Define inlet boundaries with velocity, temperature, or pressure.

For velocity and temperature, you can use the mach number calculator to identify the velocity value.
Define initial conditions for pressure and temperature.

Tip:

General usage

Analysis must be transient.
Heat transfer should be on with or without turbulence active.

Inflow boundary conditions

Stagnation pressure inlet and static pressure outflow are the preferred boundary condition specifications.
Subsonic conditions require two variables as input while supersonic conditions require three.
Mach number is computed by $M a c h = \sqrt{γ R T}$ and positivity of both pressure and temperature are checked by AcuPrep.
When the specified inflow condition is subsonic, pressure is ignored, and only velocity or Mach number and temperature are used as the boundary conditions.

Outflow boundary conditions

Subsonic: The user-specified pressure is fixed.
Supersonic: The user-specified pressure is ignored if it is lower than the computed pressure on the outflow surface.

Nodal initial conditions

It is important (critical in most cases) to specify valid initial values for all the solution quantities. Pressure and temperature must be defined such that density is realistic.