Shubham Goswami, PhD

Shubham Goswami, PhD

Postdoctoral Associate at University of Calgary

Introduction to CFD

4 minute read

Published:

This blog post provides a brief introduction to CFD, OpenFOAM and myself!!!.

Accodring to wikipedia, “Computational Fluid Dynamics (CFD) is a branch of fluid mechanics that uses numerical analysis and data structures to analyze and solve problems that involve fluid flows.” In the realm of CFD, simulations are conducted using either commercial or open-source tools to model, estimate, and predict fluid flow without the necessity for physical experiments. Consequently, CFD emerges as a potent tool for comprehending and resolving real-world physical processes, encompassing internal flows like those in pipes/channels and external flows such as aerodynamics around vehicles/structures. To delve into these simulations, one must acquaint themselves with various CFD tools. Commercial packages like ANSYS, Star CCM+, and COMSOL, as well as open-source counterparts like OpenFOAM, NEK5000, and SU2, offer diverse options. While commercial tools furnish robust simulations and user-friendly interfaces with visually appealing outputs, open-source tools, exemplified by OpenFOAM, grant freedom of use contingent on an understanding of the underlying mechanics within the blackbox.

OpenFOAM (Open Field Operation And Manipulation) stands out as a widely adopted C++ based toolbox for CFD. Its popularity has soared in recent years, evident in its extensive user base and endorsements from notable companies such as Mercedes, BMW, Volkswagen, and Intel, among others. The tool’s prevalence extends to academic research, particularly in fields like turbulence, exa-scale modeling, and general problem-solving. However, mastering OpenFOAM involves overcoming a steep learning curve, demanding advanced user expertise to align critical physics with numerical algorithms. However, delving into OpenFOAM is not a walk in the park. It entails a substantial learning curve, requiring users to possess a level of advanced expertise in identifying crucial physics, and effectively aligning them with numerical algorithms. To elaborate further, one must grasp the underlying physics of the specific problem at hand, navigate intricacies like meshing, pre-processing, and post-processing within the CFD workflow, and only then address pivotal concerns surrounding verification and validation.

This article marks the initial installment in a series aimed at guiding CFD enthusiasts and new researchers through the realm of Computational Fluid Dynamics, specifically with OpenFOAM. The author, Shubham Goswami, a PhD researcher at the University of Alberta specializing in the study of flow around obstacles (to put it crudely), shares insights gained through personal experiences in CFD. These articles serve as a valuable starting point for individuals embarking on their CFD journey, offering guidance on the intricacies of the field, from understanding physics to tackling challenges in verification and validation.

Get ready for an exciting preview of what lies ahead! Here’s a sneak peek at some topics I’ll be delving into in my upcoming articles:

  • Installing OpenFOAM on Ubuntu and Windows WSL: A comprehensive guide to compilation.
  • First Steps : Setting up your first case.
  • “4 Tutorials to Rule Them All”: Unveiling a series of tutorials for beginners in the “First Glimpse” series.
  • Why Am I Getting These Errors?: A premier exploration into debugging in OpenFOAM, covering the basics.
  • Does This Look Okay?: A guide to verification and validation, ensuring the reliability of your simulations.
  • Colorful or Computational Fluid Dynamics?: Navigating post-processing techniques to interpret and enhance your understanding of CFD results.
  • And much more to come… Stay tuned for a captivating journey into the world of Computational Fluid Dynamics!

As we embark on this exploration into the realm of Computational Fluid Dynamics, brace yourselves for a journey filled with insights, tutorials, and a deeper understanding of OpenFOAM. The upcoming articles promise to unravel the intricacies of compilation, debugging, verification, and validation, offering you a comprehensive toolkit for mastering CFD. I invite you to join me in this adventure, as we navigate through the fascinating landscape of fluid dynamics simulations. Whether you’re a seasoned CFD enthusiast or a novice researcher, there’s something for everyone in the exciting chapters that lie ahead.

Stay tuned for a wave of knowledge, practical tips, and perhaps a few surprises. Until then, happy simulating!

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Simulating Pure Pitching and Heaving Motions in OpenFOAM

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Dynamic mesh techniques in Computational Fluid Dynamics (CFD) are pivotal for capturing fluid-structure interactions and other phenomena involving motion. In OpenFOAM, the prescribed motion method allows users to simulate complex scenarios using deformable meshes while maintaining computational efficiency. This article further explores the prescribed mesh motion technique, with a specific focus on simulating pure pitching and pure heaving motions. By the end of this guide, you’ll gain insights into implementing these motions in OpenFOAM and understanding their impact on flow dynamics.

Dynamic Meshes in OpenFOAM: A Deep Dive into Prescribed Mesh Motion

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Simulating real-world fluid dynamics problems often requires the ability to handle dynamic changes in the computational domain. OpenFOAM’s dynamic mesh capabilities provide the necessary tools for this purpose. This blog explores the fascinating concept of dynamic mesh motion in OpenFOAM, specifically the mesh deformation method using prescribed motion technique. I will showcase the case setup and provide a general overview of simulating mesh motion in OpenFOAM.

Meshes in Motion: Making OpenFOAM Go with the Flow

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Simulating flows with moving boundaries and deforming geometries requires specialized computational techniques, and OpenFOAM offers robust tools to tackle such challenges. Dynamic meshes enable mesh motion and deformation, allowing simulations to accurately capture phenomena like valve operations, moving pistons, or deforming structures. In this blog, we will explore the foundational concepts of dynamic meshes in OpenFOAM, covering the principles of mesh motion and their application in CFD. Whether you are a beginner or looking to deepen your understanding, this article sets the stage for harnessing OpenFOAM’s dynamic meshing capabilities.

3D DMD and Visualization with OpenFOAM and Python

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Published:

Understanding the complex, dynamic behavior of fluid flows often requires more than just time-averaged statistics. Dynamic Mode Decomposition (DMD) offers a powerful, data-driven approach to uncover the temporal evolution of coherent structures within CFD datasets. In this blog, we’ll dive into the process of applying DMD to three-dimensional flow fields simulated using OpenFOAM and visualize the resulting modes with Python and ParaView. By combining these tools, we can unravel the intricate interactions that define unsteady flows, providing insights into both dominant patterns and transient dynamics.