What’s New in Ansys Fluent 2025 R2: My Favorite Highlights

What’s New in Ansys Fluent 2025 R2: My Top Highlights

Ansys Fluent 2025 R2 brings a host of exciting updates across solvers, interfaces, and workflows. Whether you’re using the CPU or GPU solver, PyFluent, the Web UI, or the traditional desktop interface, there’s something new to enhance performance and usability. In this post, I’ll highlight some of my favorite features from this release—especially the ones that stand out for their technical depth and user impact.

GPU Solver: Surface-to-Surface Radiation (S2S)

Two significant updates make the S2S radiation model even more powerful in GPU-based simulations:

1. Performance Boost: The S2S model now runs 2 to 2.5 times faster compared to previous releases. This means faster thermal radiation computations in enclosures with non-participating media—especially useful for high-fidelity modeling of radiative heat exchange.
2. Sliding Mesh Compatibility: S2S is now supported in sliding mesh scenarios. This is ideal for simulations where a stationary hot surface interacts thermally with a rotating component, unlocking more accurate and efficient modeling of dynamic systems.

While other radiation models can compute surface-to-surface effects, the S2S model remains the most efficient for these enclosure-type problems. 

GPU Solver: Volume of Fluid (VOF) with Species Transport (Beta)

The GPU solver now supports a beta feature that combines VOF with species transport—a powerful new capability for multiphase, multicomponent simulations:

• Supports multiple fluid phases, each with distinct species mixtures
• Compatible with sliding mesh and frame motion
• Works in both steady-state and transient modes
• Materials can exhibit variable density and non-Newtonian behavior

This is particularly useful for complex mixing processes, such as multiphase stirred reactors, where each phase can carry its own species mixture and behave differently.

Battery Modeling: Thermal Abuse Model

A new Battery Thermal Abuse framework offers more flexibility and control for safety and failure-mode simulations:

• Supports an n-equation formulation, extending beyond the previous 1- or 4-equation models
• Users can import abuse reaction rate files with any number of reactions
• Available across the CPU solver, PyFluent, and both Web and Desktop UIs

This generalization allows for more realistic thermal runaway predictions and better integration of custom abuse scenarios in battery design and safety studies. 

Usability: Renaming Expressions

Fluent now allows users to rename expressions across all solver and UI types—a small but impactful quality-of-life improvement:

• Previously, renaming required copying an expression to a new name (breaking dependencies in the process)
• Now, you can rename an existing expression, and Fluent will automatically update all dependencies

This streamlines expression management, especially in complex simulations with layered parameter definitions.

AI Assistance: Engineering CoPilot

The new Engineering CoPilot enhances Fluent’s built-in support tools:

• Integrated directly in the Fluent ribbon under Learning & Support
• Combines access to documentation, guided learning, and case tracking in one location
• Backed by AI, CoPilot delivers quick answers, helpful references, and faster support navigation

It’s a smart evolution from previous static links—putting decades of Ansys knowledge at your fingertips, all within the Fluent interface.

Final Thoughts

Fluent 2025 R2 shows Ansys’s continued commitment to performance, usability, and industry-driven workflows. From GPU acceleration and multiphysics integration to small but meaningful UI upgrades, this release brings tools that can speed up your work and expand what’s possible in your simulations.

Stay tuned for deeper dives into specific features, benchmarks, and hands-on use cases!

Ozen Engineering Expertise

Ozen Engineering Inc. leverages it's extensive consulting expertise in CFD, FEA, thermal, optics, photonics, and electromagnetic simulations to achieve exceptional results across various engineering projects, such as those involving fluid flow and heat transfer.

We offer support, mentoring, and consulting services to enhance the performance and reliability of your product or system. Trust our proven track record to accelerate projects, optimize performance, and deliver high-quality, cost-effective results for both new and existing systems. For more information, please visit https://ozeninc.com.