how to create stagnant smoke?

[achinta-mohana]

Can anyone tell us how to create non-toxic stagnant smoke for use in our experiment to visualize flow through airfoils?

We tried using fog machines, however they have very high initial velocity so they affect the flow.

Can you help us with some chemical reactions which don't require much heating and produce visible fumes?

[CaptainPanic]

If your smoke is perfectly mixed with the air, then you won't see the flow of air... because every bit of air contains the same amount of smoke.

 

Did you make a wind tunnel?

 

I know the following idea is a bit disgusting, but how about simple cigarette smoke? You can create small amounts, to show an air flow without filling the entire experiment with smoke. It's very simple to do, and should be easy to repeat.

 

In addition, this smoke is produced continuously.

 

Please note that cigarette smoke is dangerous to your health. Other types of smoke also have a chance of being unhealthy.

 

If you're under the legal age for smoking, ask whoever is your supervisor to assist and advise you about this.

 

The reason why I don't advise a chemical reaction for smoke is that they usually become really hot: that also creates an impressive amount of turbulence... which will ruin your experiment.

[Lance]

When I was experimenting with lasers I always used sparklers to create smoke to make the beams visible.

[swansont]

When I was experimenting with lasers I always used sparklers to create smoke to make the beams visible.

 

That's OK if you don't have any other optics around. I've used dry ice and liquid nitrogen to show lasers in those cases (in my lab, a sparkler would only induce the question of where to hide the body of the perpetrator). But I think the important criterion in the OP is to not have any net flow from the source of the smoke; a sparkler is hot, so there will be convection.