Accelerating Automotive CFD Simulations with High-Performance Computing

Automotive external aerodynamics simulations require a high level of accuracy in a short amount of time. Because of the large, complex geometries and domain size needed, pre-processing and solving time can be significant.

Ansys has been making great progress in accelerating the pre-processing and solving time for these types of simulations. Ansys Fluent has added new features and capabilities to generate a high-quality mesh quickly and efficiently, including:

• Task-based workflows for clean and dirty computer-aided design (CAD) geometries.
• Automation and customization.
• New meshing topologies.
• Highly scalable parallel meshing.

Ansys is also delivering significant high-performance computing (HPC) enhancements with each new release of Fluent to reduce the time it takes to arrive at reliable solutions.

Accelerating Pre-Processing

Fluent offers two different workflows that help accelerate meshing by organizing the process into a user-friendly, task-based workflow: A watertight geometry workflow for clean CAD and a fault-tolerant meshing workflow for dirty CAD.

Both workflows offer relevant choices and options, but also have the flexibility to be customized.

Best practices are embedded into each task in the form of default values. Advanced users can easily check a box to reveal more options. You can also automate the process, using a Python-based journal file for batch meshing.

Fluent also offers a new mesh topology, known as Mosaic Poly-Hexcore. Mosaic technology enables polyhedral connections between disparate mesh types. Mosaic Poly-Hexcore is the first to employ this technology. It is a combination of hexahedral, isotropic poly prism and mosaic polyhedral elements.

Because the core volume mesh is generated using hexahedral elements, the same grid resolution results in a total face-count reduction. This delivers faster compute times with lower memory and disk space requirements.

Volume meshing can be accelerated even more by using Fluent’s parallel meshing capabilities. Fluent has the ability to generate over 10 million cells per minute when running on 256 cores.

Reducing Time to Reliable Solutions with HPC

To enable fast and accurate simulations, Ansys delivers significant HPC enhancements with each new release of Fluent. One important development area is related to sliding mesh applications. They are increasingly being used to accurately simulate aerodynamic drag of a vehicle with rotating wheels, power losses in geared transmissions and the aeroacoustics of an automotive blower, for example.

Ansys 2020 R2 has enabled a 61% speedup vs. Release 19.0 for a
140-million cell Formula One car simulation on 1,280 CPU cores.

Because sliding mesh applications are typically less efficient in terms of parallel processing, Ansys has steadily removed the bottlenecks to parallel scalability of complex models. The intersection algorithms have been improved, the mesh update overhead has been reduced and the data exchange strategies have been enhanced, among other improvements. In the current release, Ansys 2020 R2, this has enabled a 61% speedup — with respect to Release 19.0 — for a 140-million cell Formula One car simulation on 1,280 CPU cores.

Ansys and Intel worked together to build a new smoother
and optimize it for Intel® Xeon® Scalable processors.

Because hardware and software improvements go hand in hand, Fluent is optimized for the latest hardware technologies including those of Ansys HPC partners like Hewlett Packard Enterprise and Intel. For example, Ansys and Intel worked together to build a new smoother and optimize it for Intel® Xeon® Scalable processors to help reduce long simulation times. The testing showed that this produces a performance boost of 12 to 19%. If you would like to know more, download the "Run Your Ansys Fluent Simulations at Top Speed" white paper.

Thanks to these and other HPC enhancements with each new release, you can solve smaller models and higher-fidelity models more quickly.

Register for our upcoming webinar, "How Aston Martin Red Bull Racing delivers winning CFD with Partners Ansys and HPE," to learn how Aston Martin Red Bull Racing is using Fluent with HPC solutions from Hewlett Packard Enterprise to increase their success on the track.