I've mentioned I'm working on a project involving fans.

I finally got the fans together and I have enough power.  The next trick is actually get the things set up properly and working.

I'm close, but the end result is unstable, and it's really hard to see what you're doing wrong when you're dealing with things that are invisible (airflow)..

I'm looking for a way to actually see what's going on so I can make adjustments.

This is indoors, so I don't want to use smoke or anything that would discolor the walls and ceiling.

That said, the best idea I've been able to come up with so far is to get some dry ice in water and put that at the center of the airflow I'm trying to map.

No idea if this will actually work or if it'll all dissipate before I can see anything.

Does anyone have any ideas they might share?

Rent a fog machine?

Dry ice

The other half (an aerospace engineer so guy that pisses around with air flow) suggests maybe a powder paint, but not too much and do not breathe it in or let anything spark near it.

He also reckons you could light a few fags if you only need to see a small amount of the air flow, but I'm guessing you mean you want to see it throughout the room?

Put a ribbon on the end of a stick.

Talk to your local hardware store, see if they stock smoke markers used by chimney sweeps to test if a chimney is unobstructed.

They are generally used indoors and should not mark, stain or leave residual smell. I would recommend testing beforehand though maybe on a piece of old drywall or sheet of paper.

Dry ice is tough to work with and it only clings to the ground. Not sure what the answer is though (perhaps you have a sketch?).

I think we're going to try the dry ice to start with (I at least know where to get it)... But thanks all, at least now I have a plan B.

If I can't get it perfect (and I might not be), I think I still have it good enough for what I need.  Will just take a lot longer and be a lot more starts and stops...

Hope you have better luck than I did.

A model wanted her hair blowing so I borrowed an industrial fan from a friend and we did a set up.

Her hair was too heavy, even when she tossed it up into the wind of the fan it just fell back down.

Fucker blew everything else in the room all over the place.

Turns out dry ice is worthless, but we made progress anyway.

Can you get a linear air flow meter? Then you can record the readings on paper in 3D.

Take a peek at another, nearby, thread...  We've got it working more or less.  Not perfectly, but actually think the low ceiling on the room is one of the bigger culprits...

Toilet paper