Streakline : Pocket CFD

Draw a shape with your finger and watch real fluid dynamics happen around it.

Streakline is a lattice Boltzmann wind tunnel that runs entirely on your phone. Sketch a
wing, an aerofoil, a car profile — or import a photo of a sketch on paper — and the solver
computes the flow around it in real time, live, at your fingertip.

WHAT YOU SEE

- Velocity, vorticity and pressure fields, in colour, updating as it solves
- Streaklines and streamlines that show where the air actually goes
- Live drag and lift coefficients, with a history plot
- Vortex shedding, separation, stagnation points and wakes — the real behaviour, not an
animation

WHAT YOU CAN DO

- Draw any shape freehand, erase and refine it
- Pick from a library of reference geometries: cylinder, flat plate, teardrop, NACA
aerofoils, slotted flaps, a multi-element high-lift section, open-wheel race wings, a car
profile, a Kammback and tandem cylinders
- Change inlet speed, viscosity and angle of attack and watch the flow reorganise
- See the real-world equivalent — what speed of air, water or glycerine your simulation
corresponds to for a body of a given size
- Pinch to zoom, drag to pan, and go full-screen

THE PHYSICS

A D2Q9 lattice Boltzmann solver with BGK collision, running the whole flow field on your
device. Forces come from momentum exchange at the body surface, so drag and lift are
measured from the flow rather than estimated. Reynolds number is reported live, and the
solver tells you when it has raised viscosity to stay stable.

FREE AND PRO

The free version gives you three hand-drawn simulations every day, the standard shape
library and the draft grid — enough to actually use, every day, forever.

Streakline Pro is a ONE-TIME PURCHASE. No subscription, nothing renews.

- Unlimited drawn geometries
- Import a PNG or photograph a sketch, with a crop and threshold editor
- Fine and Ultra grids that resolve separation the draft grid smears out
- The extended shape library, including the race wings and multi-element sections
- Save your own shapes and reload them
- Export the coefficient time series as CSV
- Record the simulation to video, watermark-free

WHO IT IS FOR

Engineering and physics students, aerodynamics enthusiasts, teachers who want something
visual, and anyone curious about why a wing lifts or why a sphere drags.

A NOTE ON ACCURACY

Streakline is an educational and exploratory tool. The simulation is two-dimensional,
weakly compressible, has no turbulence model, and runs on a grid coarse enough to be
real-time on a phone. It is superb for building intuition and comparing shapes against each
other. It is not validated engineering software, and its numbers should not be used for
design, certification or safety decisions.

PRIVACY

No accounts. No ads. No analytics. No tracking. The simulation runs on your device and your
drawings never leave it.