Leverage PyAnsys tools to streamline meshing, setup, solving, and post-processing—all from Python scripts.
Challenges
Ansys Fluent is a trusted and powerful CFD solver, widely used across industries for its high-fidelity results and flexibility. Over time, users have developed a variety of workflows to fit their simulation needs—ranging from quick design studies to complex multiphase analyses. Most of these workflows are built around the graphical user interface (GUI), which offers a user-friendly and interactive environment for pre-processing, solving, and post-processing tasks.
However, as simulation requirements become more demanding—whether due to tighter design cycles, increased model complexity, or the need for integration with external data sources—engineers and organizations alike are facing a growing need to automate and streamline their simulation workflows. In particular:
- Repetitive tasks consume valuable time and are prone to human error.
- GUI-based processes are less scalable for large projects or high-throughput environments.
- Integration with external data or optimization tools is limited through the GUI alone.
To address these limitations, Ansys has introduced a more flexible approach to simulation control through Python integration. PyAnsys is a suite of open-source Python libraries that provide programmatic access to various Ansys tools, including Fluent through PyFluent. This shift toward scriptable, code-driven workflows opens the door to more efficient and scalable solutions. Still, it brings its own set of challenges:
- Users must learn new tools and adopt Python programming practices.
- Simulation processes need to be restructured to support automation.
- Teams may need to invest in training, documentation, and version control strategies.
Despite these hurdles, the potential benefits are significant:
- Improved reproducibility and consistency across simulations.
- Reduced manual effort and fewer human errors.
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Seamless integration with broader engineering and data analytics workflows.
PyAnsys
PyAnsys allows users to interact with Ansys solvers in a Pythonic manner, facilitating automation and simplification of product usage through workflow scripts. PyAnsys includes several repositories, such as PyFluent, which helps in launching, interacting with, and controlling Ansys Fluent sessions from within any Python environment. This integration is particularly useful for tasks like developing post-processing backend programs or combining Ansys simulations with machine learning applications.
Engineering Solutions
PyFluent is an open-source technology within the PyAnsys ecosystem that provides powerful APIs to interface with Ansys Fluent. It enables users to automate repetitive tasks, build custom workflows, and create fully scriptable simulation environments using Python. With PyFluent, the entire simulation pipeline—from pre-processing and physics setup to solving and post-processing—can be controlled programmatically.
To support various stages of a Fluent simulation, PyFluent is organized into modular components:
- PyFluent-Core. Access to meshing, solver and basic post-processing (link).
- PyFluent-Parametric. Access to Ansys Fluent's parametric workflow capability (link).
- PyFluent-Visualization. It extendes the post-processing and visualization capabilities (link).
Together, these modules give engineers the flexibility to script entire CFD workflows, integrate Fluent into larger engineering pipelines, or link simulations with data science and machine learning tools. Some frequently asked questions about PyFluent include:
- Python Compatibility. PyFluent supports Python 3.7 and newer.
- Ansys Version. It is compatible with Ansys Fluent 2022 R2 and later, on both Windows and Linux platforms.
- IDE Support. Users can work comfortably with a variety of development environments, such as Visual Studio Code, Spyder, or Jupyter Notebook.
Installation
Before working with PyFluent, you need to ensure that Python, the necessary PyFluent modules, and any additional required Python libraries are installed on your system. There are two main ways to install Python and manage your environment:
- Conventional method. You can manually install Python from the official Python website and then use
pipto install the required PyFluent packages and dependencies. - Ansys Python Manager. This is a more user-friendly option provided by Ansys. It allows you to install Python, create and manage virtual environments, and easily install PyFluent packages within those environments. It streamlines the setup process, especially for users working within the Ansys ecosystem (Link).
Methods
To help users get started, Ansys provides a variety of example applications that demonstrate how Fluent’s capabilities can be accessed and controlled through Python scripting. These examples cover the full simulation workflow, showing how to automate tasks such as importing geometry, generating meshes using Fluent’s meshing tools, configuring physical models and boundary conditions, running the solver, and reviewing results through Fluent’s post-processing features.
By exploring these examples, users can better understand how to build custom automation scripts, tailor simulation procedures to specific needs, and integrate Fluent into larger, Python-driven engineering environments. The figure below presents some of the typical cases offered by Ansys to illustrate these possibilities.
Results
To better illustrate how PyFluent can be applied in real simulation workflows, we will now walk through one of the example cases provided by Ansys: the Ahmed Body external aerodynamics simulation.
The Ahmed Body is a well-known simplified car model commonly used in aerodynamic studies to evaluate flow separation and predict drag and lift forces. Its geometry features a blunt front and a slanted rear surface, making it a benchmark case for studying external flow behavior in automotive applications.
In this example, the PyFluent API is used to carry out a full simulation of the Ahmed Body, covering the complete CFD workflow, including:
- Importing the geometry/CAD model
- Meshing the geometry
- Setting up the solver
- Running the solver
- Post-processing the results
We invite readers to explore how this example handles the initial stages of the simulation—geometry import and mesh generation—using PyFluent. These steps demonstrate how the CAD model of the Ahmed Body is programmatically loaded into the workflow and how Fluent’s built-in meshing capabilities can be controlled through Python scripting. For the purpose of this blog, however, we will focus on the setup and post-processing stages.
Solver Setup and Solve Workflow
Define Constants
Define Materials
Define Boundary Conditions
Define Reference Values
Define Solver Settings
Define Report Definitions
Initialize and Run Solver
Post-Processing Workflow
Simulation Results Visualization
Saving the case file and closing the session
Ansys Solution Benefits
CFD modeling demonstrates its potential to optimize and evaluate hydraulic structures through Ansys's advanced solutions. For preprocessing, Ansys SpaceClaim and Discovery Modeling facilitate CAD creation and preparation, while Ansys Fluent and CFX tackle various simulation challenges. High-fidelity postprocessing tools, like Ansys Ensight, effectively analyze and visualize large datasets.
Additionally, CFD results can be integrated with structural analyses in Fluid-Structure Interaction (FSI) scenarios, supported by Ansys Mechanical and LS-Dyna. Techniques such as Design of Experiments (DOE) and advanced optimization are facilitated by DesignXplorer and Ansys OptiSlang within the Workbench platform. Ansys also provides HPC licenses and GPU capabilities for parallel processing of complex models, ensuring thorough evaluations.
Ozen Engineering Expertise
Ozen Engineering Inc. leverages its extensive consulting expertise in CFD, FEA, optics, photonics, and electromagnetic simulations to achieve exceptional results across various engineering projects, addressing complex challenges like multiphase flows, erosion modeling, and channel flows using Ansys software.
We offer support, mentoring, and consulting services to enhance the performance and reliability of your systems. Trust our proven track record to accelerate projects, optimize performance, and deliver high-quality, cost-effective results for both new and existing water control systems. For more information, please visit https://ozeninc.com.
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