Real-Time Flow Control with Lorentz Forces ⚡🧲

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Discover how engineers use Lorentz Forces, and AI to control fluid flows in real time—without any mechanical parts!

Published July 20, 2025 By EngiSphere Research Editors
Lorentz Forces © AI Illustration
Lorentz Forces © AI Illustration

TL;DR

A recent research demonstrates real-time control of weakly conducting fluid flows using Lorentz Forces, powered by Koopman-based machine learning.


The R&D

Controlling how fluids flow isn’t just something for nature documentaries 🌊—it’s at the cutting edge of engineering research. From designing faster planes ✈️ to creating more efficient industrial mixers 🧪, fluid control has huge applications. But how do you steer a flowing liquid, especially one that can’t be touched? 🤔

That’s exactly what a team of researchers from the Czech Technical University and LAAS-CNRS tackled in their latest study on real-time control of magnetohydrodynamic (MHD) flows. And the best part? They did it without touching the fluid at all—using only Lorentz Forces ⚡🧲, and clever machine learning tricks 🖥️.

Let’s break it down in plain language—engineer-to-engineer!

🌐 What’s Magnetohydrodynamics (MHD) and Why Does It Matter?

In simple terms, MHD deals with how electrically conducting fluids behave in the presence of electric and magnetic fields. Think seawater 🌊, liquid metals 🩶, or electrolytes 🧪.

✅ Why it's cool:

  • You can steer or stir the fluid without any mechanical parts.
  • No pumps, no paddles—just smart use of electromagnetic forces.

✅ Where it’s useful:

  • Space propulsion systems 🚀
  • Metal casting industries 🏭
  • Cooling systems in nuclear reactors ☢️
  • Even astrophysical studies! 🌌

But here's the catch: fluids are already notoriously hard to control because of turbulence and chaos. Add electromagnetic effects and things get way more complicated. 😬

🧲⚡ The Big Idea: Using Lorentz Forces to Control the Flow

The researchers used a shallow dish filled with a weakly conducting liquid (water + sulfuric acid). Around it, they placed:

  • 4 electrodes 🔋 to generate electric fields
  • 4 electromagnets 🧲 to create magnetic fields
  • A camera system 📷 to watch the particles in the liquid and measure flow speed.

Here's the magic sauce:

Electric field + Magnetic field = Lorentz Force, which pushes and pulls the liquid in different directions.

By tuning the electricity and magnet strength in real-time, they could shape the flow into vortices, jets, and other patterns! 🎨

🎯 The Brain of the System: Machine Learning with Koopman Operators

Now, you might wonder: how can we predict and control such a chaotic system in real time?

Instead of solving complex fluid equations (which take hours to compute), they used a data-driven approach powered by the Koopman operator.

🧠 What’s a Koopman Operator?
  • It transforms complex, nonlinear systems into simpler, linear ones.
  • It’s like turning a spaghetti of chaos 🍝 into neat, predictable lines 📈.
  • Linear models = fast computations = real-time control ✅.

They trained the model by observing how the fluid moved in response to different electric/magnetic inputs. Using this, they built a Koopman-based Model Predictive Controller (KMPC) that predicts future flow and adjusts controls on the fly! 🖥️🤖

💻 Real-Time Control—On a Laptop!

One of the most impressive feats? The whole thing runs on a standard laptop 💻!

Performance Highlights
  • Control decisions calculated every 0.5 seconds.
  • Full loop (measurement + control) runs without delays 🚀.
  • Used convex optimization for speed, breaking a tough problem into two easy steps:
    • Control electrodes 🟠
    • Control electromagnets 🟣
  • Fast, efficient, and practical—no supercomputer needed.
🧪 Experimental Results: Shaping the Flow Like a Conductor Leads an Orchestra 🎻

The team conducted multiple experiments to test flow control:

✅ Velocity Control

They created different flow shapes:

  • Two Vortices 🌀🌀
  • Jet Stream 🌬️
  • Side Shear Flow ↔️
  • Cross Patterns ✖️

Result?
In all cases, the fluid adapted to the desired pattern within seconds and remained steady—an incredible feat for chaotic fluids!

✅ Vorticity Control

They even controlled vorticity (how much the fluid spins):

  • Created a spinning vortex 🌀
  • Switched direction halfway through the experiment!
  • The system adjusted smoothly to the new spinning direction.
📈 Why This Research Matters: Real-World Engineering Impact

This study isn’t just a fancy lab experiment—it shows that:

  • Real-time control of complex flows is possible without traditional models.
  • Using electric and magnetic fields offers a contactless way to manipulate flows, reducing mechanical wear.
  • The Koopman operator approach is efficient, meaning real-world industrial systems could adopt this technology.
Future Possibilities 🏆

✅ Advanced mixing systems 🧪
✅ Efficient cooling for electronics 🖥️
✅ Contactless medical devices 💉
✅ Smarter fluid-based robotics 🤖
✅ Better flow control in aerospace and automotive industries 🚀🚗

🚀 The Future of Flow Control: Smarter, Faster, and More Efficient

This research shines a spotlight on a future where engineers don’t have to wrestle with complicated fluid equations, but can train models and use data to control complex systems in real time.

The fusion of:

  • Magnetohydrodynamics (MHD),
  • Lorentz forces,
  • Koopman operators, and
  • Real-time optimization
    opens doors to more efficient, smarter, and contactless engineering solutions across industries.

And all of this is run on a laptop—proving how accessible and scalable this technology can be for engineers worldwide. 🌍

📝 Summary for Engineers
✅ Feature💡 Details
🧲 Control TypeElectric & Magnetic Fields
🛠️ MethodKoopman Model Predictive Control (KMPC)
⚙️ Setup4 electrodes + 4 electromagnets + camera
💻 HardwareStandard Laptop (real-time)
🌀 ControlledFlow velocity & vorticity
🎯 ApplicationsMixing, cooling, robotics, aerospace
Final Thoughts 💭

This work is an excellent showcase of how engineering, machine learning, and fluid mechanics can merge into practical, high-performance systems. 🌟

As fluid engineers, researchers, or industrial designers, this approach offers a new way to think about flow control—faster, smarter, and contactless.


Concepts to Know

Magnetohydrodynamics (MHD) - How liquids that conduct electricity (like saltwater or plasma) behave when exposed to electric ⚡ and magnetic 🧲 fields.

Lorentz Force - The invisible push ✋ a fluid feels when electric and magnetic fields interact—like steering water with magnets!

Model Predictive Control (MPC) - A smart controller that predicts the future 🔮 of a system and adjusts actions in real time for best performance. - More about this concept in the article "Turning Waste into Watts 💧💡 How Smart Control is Powering Energy-Free Wastewater Plants!".

Koopman Operator - A mathematical trick that turns complex, chaotic systems into simple linear models 📝 so computers can predict them fast. - More about this concept in the article "🚄 Leveling Up Maglev Trains: How Data Makes Them Float Better!".

Vorticity - How much a fluid spins or swirls 🌀—high vorticity means strong circular motion, like a mini whirlpool!

Particle Image Velocimetry (PIV) - A camera-based technique 📷 that tracks particles floating in liquid to measure how the fluid flows.


Source: Adam Uchytil, Milan Korda, Jiří Zemánek. Real-time control of a magnetohydrodynamic flow. https://doi.org/10.48550/arXiv.2507.12479

From: Czech Technical University in Prague; LAAS-CNRS, Université de Toulouse.

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