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.