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Solver Help
More resources for AcuSolve and ultraFluidX solvers.
ultraFluidX User Guide
View detailed information regarding the features, functionality, and simulation methods available in ultraFluidX.
Use ultraFluidX
Check system requirements and launch ultraFluidX.

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.
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.
- AcuSolve Help
  Click here to access AcuSolve online help.
- ultraFluidX User Guide
  View detailed information regarding the features, functionality, and simulation methods available in ultraFluidX.
  - Overview
    ultraFluidX is a simulation tool for the prediction of the aerodynamic properties of passenger and heavy-duty vehicles, as well as for the evaluation of building and environmental aerodynamics.
  - Use ultraFluidX
    Check system requirements and launch ultraFluidX.
    - Additional Command Line Options
      Starting ultraFluidX with the parameter -h (ultraFluidX -h) exposes additional command line options and special ultraFluidX functions without license checkout in the terminal.
    - Workflow and Output
      After ultraFluidX has been launched, it will read in the tessellated surface mesh, as well as the simulation parameters, and then start to generate the volume mesh based on the specified refinement zones.
    - Multi-Node Usage
      ultraFluidX can generally be used on an arbitrary number of compute nodes.
  - Simulation Parameters
    Available parameters for defining simulations in ultraFluidX.
  - Expert Parameters
    Additional expert parameters can be used to fine-tune simulations.
  - Post-Processing Tools
    For certain aeroacoustics applications, such as fan noise, HVAC noise and train community noise, you need to evaluate flow-induced noise levels at microphones located far away from the turbulent regions simulated in ultraFluidX.

View All Altair HyperWorks Help

Use ultraFluidX

Check system requirements and launch ultraFluidX.

Before using ultraFluidX, make sure that enough compatible GPU devices are available on your machine(s) for your desired simulation, especially in terms of available memory on the devices and their compute performance.

ultraFluidX requires at least one NVIDIA GPU device with compute capability 3.5 or higher and NVIDIA drivers version 450.80.02 or higher, and it is strongly recommended to use a minimum of four GPUs based on the NVIDIA Ampere Architecture, for example, NVIDIA A100, to allow for overnight simulations of typical passenger-car setups on a single machine.

ultraFluidX always needs MPI to run a simulation. The main rank, 0 handles the preprocessing and the I/O, whereas each additional secondary rank 1...n handles one GPU device each. Therefore, ultraFluidX must be started with a minimum of 2 MPI ranks to use at least 1 GPU device for the simulation.

To start ultraFluidX on 4 GPU devices for example, execute the BASH command,

mpirun -np 5 ultraFluidX case.xml

case.xml specifies the simulation parameters and needs to reference a tessellated surface mesh in STL format, a small example (cube.xml, cube.stl) is located in the installation folder uFX/examples/cube/.

If there are more GPUs available than needed for running the simulation, the number of GPUs that is accessible by ultraFluidX can be selected via the environment variable CUDA_VISIBLE_DEVICES, that is, by executing the BASH command,

export CUDA_VISIBLE_DEVICES=0,1,2,3

in your terminal to restrict the usable GPUs on the respective machine to devices 0 to 3.

CAUTION: If ultraFluidX cannot find as many GPU devices as you expect to be available on your machine, verify that CUDA_VISIBLE_DEVICES has not been set unintentionally.

For convenience, ultraFluidX can also be launched via the uFX script in the altair/scripts folder:

ufx -np 5 -inpFile case.xml

The script sets the required environment variables, wraps the mpirun call, and redirects the output of ultraFluidX into a .log file that is automatically tagged with the current time stamp.