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WindFlow

Watch the air. Compare shapes.

Play with cars and planes in a 3D wind tunnel on iPhone. Watch streamlines and animated arrows, compare shapes, learn drag. Import your own print when you’re ready. On-device screening estimate — not a lab test. No account. Gallery free.

Get WindFlow on the App Store

WindFlow on iPhone showing colored streamlines around a race car in a 3D tunnel.

Who it’s for

WindFlow is a pocket wind tunnel for students, teachers, and makers. Watch streamlines, compare shapes, and learn drag on iPhone. The number on the card is an on-device estimate, not a lab test.

  • Students

    Watch the wake curl. Learn what drag, lift, and Reynolds number mean at the size of the model in your hand. The picture comes before the digits.

  • Teachers

    Pass an iPad around. There is no login. Use the run as a demo and a discussion, not as a graded lab report or a substitute for a physical experiment.

  • Makers

    Import the print you are about to make. Round the nose, taper the tail, and look for a cleaner wake. That is the workflow. Matching a catalog Cd is not.

  • Families

    Gallery cars and planes are free to play with. No account. Age rating 4+. WindFlow is family play, not a childcare product, and it does not certify toys.

Look around

Force tools on a race car: wheel-spin arrows and aim controls.
Orbit view of streamlines passing a race car, colored by speed.
Import screen for a 3D print, with on-floor placement and yaw and pitch.
Airflow setup with Walk, Bike, and Car speeds and a Run simulation button.
Share sheet for an image, a video clip, or a PDF report.

On this iPhone

  • See streamlines

    A live 3D lattice-Boltzmann solve fills the tunnel with streamlines and animated arrows. The arrows travel along the lines as the estimate settles, so you can watch the wake move.

  • Import a print

    Bring STL, 3MF, OBJ, PLY, AMF, USDZ, or GLB. Geometry is voxelized on this iPhone. Pressure and speed paint the viewport.

  • Drag and lift

    Cd, Cl, Reynolds number, and reference area sit on a clay card. Chips say Slips through, In between, or Higher drag at this Re — a cue, not a grade.

  • Stays on the device

    Meshes never leave this iPhone. There is no account, no cloud solve, and no upload. A video, image, or PDF leaves only when you tap Share.

What you learn

  • Drag

    Drag is how hard the air pushes back. A brick fights the air. A tapered shape slips through. Cd is the screening number for that push at this size and speed.

  • Wake

    The wake is the disturbed air behind the part. A big, messy wake usually costs drag. Watch streamlines curl, or cut a slice through the air behind the body.

  • Reynolds number

    Reynolds number says how the air feels for this size and speed. A toy car at Bike speed is not a highway sedan. The app shows Re so you can say the scale out loud.

  • Compare one change

    Keep speed and the wind box the same. Change the silhouette, then run again. Students see cause and effect. Makers see whether the wake got cleaner.

On iPad

iPad view of streamlines curling in the wake behind a car.
iPad result card reading Slips through, with a speed-colored slice through the car.

How a run works

  1. Pick a gallery shape, or import your own print.
  2. Set the air: Walk, Bike, or Car, and a Fast or Finer grid.
  3. Tap Run and watch the wake settle.
  4. Read Cd and Cl, then share a clip, image, or PDF.

Free gallery, Pro for imports

Gallery play, vs clips, and gallery videos are free. One imported-part run is included.

WindFlow Pro is $4.99 a month or $34.99 a year through Apple. It unlocks unlimited imported-part runs.

Get WindFlow on the App Store

A screening estimate

WindFlow is a coarse D3Q19 lattice-Boltzmann screening estimate. It is not a laboratory wind-tunnel test, not a professional engineering service, and not airworthiness, flight-performance, or automotive certification.

Do not use it to decide whether something is safe to fly, drive, or occupy. Props and wheels stay frozen. Print-scale Reynolds numbers are shown on purpose. If a result and the real world disagree, trust the real world.

The limits are also in the Terms of Use.

FAQ

Does WindFlow upload my 3D print?

No. Import stays on this iPhone. There is no account. Sharing a video or photo is something you start.

Is this a real wind-tunnel test?

No. WindFlow is a D3Q19 lattice-Boltzmann screening estimate on a Cartesian grid. It is not a laboratory test, not FAA/EASA data, and not automotive certification.

Can I use this in class?

Yes, as a demo, not as a lab report. Pass the iPad around — there is no login.

Is the gallery free?

Yes. Play, vs-vs clips, and gallery videos are free. Importing your own print uses one free run, then WindFlow Pro.

Who is WindFlow for?

Students, teachers, makers, and families who want to watch air around a shape and compare silhouettes. It is a demo and a discussion tool. It is not a graded lab report or a certificate.

What files can I import?

STL, 3MF, OBJ, PLY, AMF, USDZ, and GLB. Geometry is voxelized on this iPhone or iPad. Meshes are not uploaded.

Why is my Cd different from a published car number?

Published Cd values are usually full-scale tunnel or coast-down results. WindFlow runs at print-scale Reynolds number on a coarse voxel grid. Compare shapes inside the app. Do not map a toy-scale Cd onto a brochure.

Does a longer solve make the result certified?

No. Extra steps clean the wake on this coarse model. They do not turn a screening estimate into a tunnel certificate or a go-ahead to fly or drive.

Does WindFlow work on iPad?

Yes. The same on-device solve runs on iPhone and iPad. There is no login, so a class can pass one iPad around.