# A New Approach in Fluid Dynamics Simulation

Simulating Without Solving Navier-Stokes Equations Using Lattice Boltzmann Method

- **Source:** [Towards Data Science](https://towardsdatascience.com)
- **Published:** 2026-07-25
- **Topic:** [Data & AI](https://brifing.si/c/data-ai)
- **Original article:** <https://towardsdatascience.com/the-fluid-simulator-that-doesnt-solve-the-fluid-equations/>
- **On Brifing:** https://brifing.si/s/6033dae2-22cb-4bf8-8a9f-c1e7b056ba81

## Introduction

Fluid dynamics simulations typically require solving Navier-Stokes equations. However, this method can pose challenges in complex geometries. The Lattice Boltzmann Method (LBM) offers a new approach to simulate fluid behavior without solving these equations.

## Kármán Vortex Street

The Kármán vortex street is the swirling pattern that forms behind blunt objects in fast flow. This phenomenon is seen behind bridge pillars and airplane wings. LBM simulates such flows by modeling microscopic particle collisions.

## Molecular Dynamics and Navier-Stokes

LBM sits between molecular dynamics simulations and Navier-Stokes solvers. This method uses microscopic particle distributions to reveal macroscopic flow behavior.

## BGK Approximation

The BGK approximation replaces complex collision operators with a simple relaxation time. This speeds up the simulation while accurately capturing Navier-Stokes equations.

## D2Q9 Lattice

LBM reduces continuous velocity space to a finite set of velocities. The D2Q9 lattice is one such set, valid for low Mach numbers. This increases the simulation's efficiency.

## Computational Ease

LBM eliminates the need for mesh generation in complex geometries. This makes simulations faster and more automated.

## MareNostrum 5 Supercomputer

This study was conducted on the MareNostrum 5 supercomputer. LBM's parallelizable structure allows it to run efficiently on such high-performance systems.

## Source Code

The full source code and a simplified Python/NumPy version are available on GitHub. This makes it easier for researchers to apply the method in their own studies.

## Theoretical Elegance

LBM derives Navier-Stokes equations rather than assuming them. This makes the method theoretically elegant and practically fast.

## Low Viscosity Limitation

LBM can become numerically unstable at low viscosities. This is one of the method's limitations and a factor to consider.

## Future Potential

LBM is a promising method in fluid dynamics simulations. Its theoretical and practical advantages open the door to new research in this field.

## Conclusion

The Lattice Boltzmann Method offers significant advantages over traditional methods in fluid dynamics simulations. This method creates new opportunities both theoretically and practically.

## Sources covering this story

- https://towardsdatascience.com/the-fluid-simulator-that-doesnt-solve-the-fluid-equations/ — 

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_Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._