# reynolds number
The Reynolds number is the dimensionless ratio of inertial to viscous forces that tells you, before you even run a simulation, whether a fluid will slide by smoothly or tumble into chaos. It's the single number engineers and physicists check first when sizing a pipe, shaping a wing or predicting when a smooth wake will start shedding vortices. This collection lets you turn that number into something visible: watch a cylinder shed a Kármán vortex street as the flow speeds up, step through a Lattice-Boltzmann Flow grid to see how the method itself resolves eddies, compare velocity profiles across a Pipe Flow Profiles simulation, or slide straight through the Laminar to Turbulent Transition to see the exact point flow stops behaving.
Found: 4 simulations · 1 articles
🧪 Simulations (4)
📖 Articles (1)
📊 Facts
How many Reynolds-number simulations are here?
4 simulations plus 1 companion article, covering everything from a single shedding cylinder to a full CFD-style lattice grid.
What's the highlight simulation?
Kármán Vortex Street is the classic entry point — it renders the alternating vortex wake behind a bluff body and has its own article breaking down the Strouhal number and the Lattice-Boltzmann Method behind it.
Which sim uses the Lattice-Boltzmann Method?
Lattice-Boltzmann Flow simulates fluid motion by tracking particle-distribution functions on a grid rather than solving the Navier-Stokes equations directly.
Where can I see the laminar/turbulent boundary directly?
Laminar to Turbulent Transition and Pipe Flow Profiles both let you push the Reynolds number up until the flow visibly breaks from smooth layers into mixing eddies.
Looking for more? Dive into the full library of 1000+ interactive, browser-based simulations, or browse every topic.