Author Topic: Quiet aerodynamic levitation  (Read 3017 times)

levitator_nav

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Quiet aerodynamic levitation
« on: May 15, 2013, 11:38:23 PM »
I'd like some advice on soundproofing a physics experiment. I was told that Randy is the moderator of these forums, which means that he'll probably see this post. Randy, you might remember, I spoke to you on the phone about this project back in fall 2012.

I want to do aerodynamic levitation, but I want to do it quietly. The standard way to do it is to point a hair dryer straight up, and then put a ping-pong ball in the air stream. Here's a video:

https://www.youtube.com/watch?v=5zD7Le2mGFg#t=35s

But hair dryers are loud. So my idea was to put the hair dryer inside some kind of box with soundproofing in it.

When I spoke to Randy, he suggested that I try it with a computer fan, because they're quiet. I did try it with a few different computer fans, and none of them worked. After some further reading, I discovered that in this experiment it's important to have a high air velocity (FPM), and it's less important to have a high volumetric flow rate (CFM). Computer fans have a low air velocity.

So I'm going back to my original idea: a hair dryer inside a soundproof box. I'd like some advice on how to construct that box. I was looking at this page:

http://soundproofing.org/infopages/generator.htm

which says that "air will go around corners well, whereas sound doesn’t like to." I'm wondering if I can use this idea, like maybe send the air stream through a square pipe. Would that work, allowing the air through, but not the sound?

levitator_nav

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Re: Quiet aerodynamic levitation
« Reply #1 on: May 15, 2013, 11:55:03 PM »
I made a few images to clarify what I mean by the "square pipe." The gray shape is the hair dryer. The dotted lines is the direction of air flow.

Randy S

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Re: Quiet aerodynamic levitation
« Reply #2 on: May 16, 2013, 03:12:43 PM »
I remember you! :)

Well, we will have to back to the drawing board , if you create the 90* turns you most likely will lose velocity as well. Obviously you have to have direct stream without obstructions.


I think your on the right track as far as putting the hair dryer in a soundproof box. You can baffle the intake and see if that gives you enough reduction.

give me a call sometime and lets throw some ideas around.

Randy S.
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

levitator_nav

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Re: Quiet aerodynamic levitation
« Reply #3 on: May 16, 2013, 09:25:02 PM »
Thanks for replying. I'll call you some time to discuss.

levitator_nav

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Re: Quiet aerodynamic levitation
« Reply #4 on: May 31, 2013, 08:17:00 PM »
Ok, so I'm sketching out the soundproofed hair dryer box, and putting some more thought into it. I have more questions. You were basically saying that I want to avoid the hair dryer contacting the walls of the box, as much as possible. Right? What would be some good materials to put between the dryer and the walls of the box? To "mount" the dryer inside the box, it seems natural to just put it up against the walls, but I feel like there should be something between them. Maybe a flat piece of rubber? If so, how thick?

We already talked before about lining with cotton towels, putting a rubber gasket at the output, and using pipe cleaners and rubber hose for attachment.

BTW, do you have an email address where I can contact you?

Randy S

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Re: Quiet aerodynamic levitation
« Reply #5 on: May 31, 2013, 09:26:39 PM »
you can e-mail me direct at

 Randy@soundproofing.org

Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040