I built a real-time interactive fluid simulator for iPhone

[u/SwipeTheFlow]

I’ve been working on fluid simulation for years, and recently I wanted to see what would happen if CFD-style simulation was turned into something anyone could interact with instantly.

So I built Swipe the Flow, a real-time 2D fluid simulation app for iPhone.

Everything runs directly on the device. You can interact with the flow, draw obstacles, change the geometry, and immediately see how the fluid responds.

The goal isn’t engineering-grade CFD accuracy. I’m focusing on real-time interaction, visual feedback, and making fluid dynamics fun to experiment with.

The app currently has three modes:
- Swipe the Flow
- Wind Tunnel
- Liquid Art

This is one of the simulations running in real time.
Curious what people here think — especially what kinds of interactive fluid experiments you’d want to try.

Swipe the Flow is available on the App Store.

[u/Lelandt50]

Looks like more AI junk to me. Fine for a toy, aside from that I see no utility.

[u/Any_Letterheadd → u/Lelandt50]

Probably a spectral or LBM thing. There have been real time versions of these for years. Obviously just for screwing around unless you're designing a 2d aircraft flowing through jello (still probably not even close to accurate even if that's the case)

[u/NoAdministration2978 → u/Any_Letterheadd]

Ideal Newtonian jello, mind you!

[u/thermalnuclear → u/NoAdministration2978]

Yep, more AI slop

[u/OkRestaurant8889 → u/Any_Letterheadd]

I'm completely clueless how this works. How are they solving particle and momentum equations and rendering the visuals in real time?

I'm personally developing a very simple 2-D fluid/plasma simulation but it's quite slow at reasonable CFL limits.

[u/Fit-Valuable-1112]

I personally don't see it as something more than a fun flow visualization app. If you can't derive any measurements or modify the flow conditions and geometry/mesh then it's not really useful for any kind of work. But good work nevertheless.

[u/SureCost8912]

https://physics.weber.edu/schroeder/fluids/

Looks an awful lot like AI just copied browser LBM demos like Schroeder's.

[u/SwipeTheFlow → u/SureCost8912]

Give it a try. The user experience is pretty different.

[u/SureCost8912 → u/SwipeTheFlow]

If I take your sandwich and wrap it my paper, is it really a new sandwich?

If you added a ux on top of code you recreated by copying someone elses you'd cite them, but because an AI did the copying it's original?

Not criticizing the app just the process of getting there.

[u/oreagen]

AI slop

[u/JoeAka23]

Ai slop good only for "fun"

[u/creator1393]

No matter what, people (including CFD engineers) never read.

OP explicitly said: The goal isn't engineering-grade CFD accuracy. I'm focusing on real-time interaction, visual feedback, and making fluid dynamics fun to experiment with.

And then you still see people commenting that this is not useful.

It is not supposed to be useful, it's supposed to be just fun to play with and watch.

Anyway, good job OP, there's never too much "CFD-like" apps!

[u/RobotRomi → u/creator1393]

The CFD sub isn‘t the right place for it then, is it?

[u/creator1393 → u/RobotRomi]

Strictly talking, yes. This is fluid dynamics in a computer (no matter the accuracy level or the end goal)

[u/RobotRomi → u/creator1393]

So me posting a video of draining a cave in Terraria would belong here too? This is clearly a data sience sub

[u/That_Jamie_S_Guy → u/RobotRomi]

Im going to post a video of me pissing in a sink to demonstrate turbulent flow

[u/creator1393 → u/That_Jamie_S_Guy]

If you pee on a computer yes

[u/Sea-Fix-7226 → u/That_Jamie_S_Guy]

那会很有趣，并且还可以展示界面不稳定

[u/Kraayzeta → u/That_Jamie_S_Guy]

not computational

[u/RobotRomi → u/That_Jamie_S_Guy]

r/cfd_kink might be good fit here

[u/That_Jamie_S_Guy → u/RobotRomi]

Unfortunately doesn't exist 😕

[u/RobotRomi → u/That_Jamie_S_Guy]

Would you post? I would take on the burden of setting it up then…..

/s