How do you build a Box Fan Wind Tunnel?

I have a Science Experiment that I am running that requires I test the aerodynamics of several objects using a wind tunnel. I do not have access to a wind tunnel or wind tunnel testing software. But I have a multimeter, a box fan, and lots of cardboard. Does any one out there know how to build a box fan wind tunnel? Help me please!!!

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lemonie7 years ago
Well here's one way:
arxiv.org/ftp/physics/papers/0208/0208039.pdf
This is another:
www.docstoc.com/docs/7183824/How-to-make-a-Wind-Tunnel

The commonality seems to be achieving an even airflow, which you can see in the designs by way of straws.

L
you keep a good watch on traffic
Happened to be around at the time. (I do work & sleep y'know)

L
(I do work & sleep y'know)
....not at the same time I hope ????

Steve
No I have usually have to be semi-conscious for working. Trouble is when I've spent an hour in bed chewing data and I wake up, I realise it was wasted effort...

L
I'd get that corrugated plastic stuff they use for packaging to make a laminar flow stack.
seandogue7 years ago
The fan will be your power source, but you need a method for creating a laminar flow field. The easiest way to do this as an amateur is to use a grid of stacked straws, like a honey comb, inside its own frame. Basically, you build a square frame and apply some insect screen to one face. Assemble the straws in the frame, then cover the opposite side of the frame with insect screen. Place the fan against this frame. Now build a test area inside a long square tube that attaches to the other side of your flow straightening section (the frame with the straws is the flow straightener . This reduces the swirl caused by the fan.  There are some rough rules for "correct operation.

1. the straws should be at least 10 times as long as their diameter
2. the section prior to where you'll test should be at least 10 times as long as it is wide.
3. Minimize interior projections (that means try to make the inside as smooth as possible. This reduces entrained turbulence

(the rules are actually alot more specific, but for a school project, this should get you started). Look up "flow straightener", "laminar flow", and "wind tunnel"

good luck