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It's always been cool to see the car commercials depicting the clean, crisp, curvature of cars (namely the Infiniti commercials).   As an aerospace/aerodynamics enthusiast, I spend my free time looking at planes and watching videos about how they work and interact with the medium they travel through, air.  For a while, I've known that planes, rockets, and even cars are designed by subjecting small scale models of them through an instrument known as a wind tunnel.  However, the wind tunnels I know of are either very big, expensive and hard to access unless you have connections or small pitiful demonstrations the science museums use show the airflow around a very limited array of  objects, often times a static display.  I've always desired to see the effects of different objects in wind tunnels for myself so when my physics teacher gave us a end-of-the-year assignment to learn about anything physics related and use what I've learned to teach the class, I thought to myself, this is a perfect moment to make a wind tunnel.  I partnered up with a peer, Ian Kelley (also interested in testing out various objects and seeing their effects) and we set out to build a wind tunnel that was simple and cool at the same time that we would be able to see the effects of air clearly on various objects.   This is a guide documenting our process and how the problem was approached.  Included are images and tips on how to make your very own tunnel cheaply in order to learn about the aerodynamic properties of objects. Hope you enjoy.
UPDATE: Be sure to check out the updated version of this project, here.

Step 1: Design & Why?

To start off, we knew the basics of wind tunnel.  A air source that is compressed, increasing the speed allowing for various objects to be tested for aerodynamics and air resistance. A source of inspration for making the tunnel was another Instructable that was made previously by user Goalieguy (http://www.instructables.com/id/Cardboard-Wind-Tunnel/ be sure to check it out!).  
We also used NASA as a resource into the design of the tunnel. 

Now that the tunnel design was set, we had to come up with a way to generate smoke.  Ian thought up of the idea of using a pump and a jar and that can be seen on the bottom right side of the diagram.  Pretty smart idea I gotta say.

Now how does a wind tunnel work? Well the physics behind it are based off the work of Daniel Bernoulli, a Swiss physicist.  Many might remember him from the equation that you learned in physics back in high school of constant= P + 1/2 p v^2 + p g h.  An equation he helped contribute to, the continuity expression in physics of A1V1=A2V2.  This provides the foundation of wind tunnels by showing how if you decrease the cross sectional area, your  speed subsequently increases.  In the case of this specific tunnel that was made, the speed increased by a factor of 3.5 from leaving the fan to being compressed by the contraction section. 
I think every school should have a wind tunnel. I have built a simple one for our school, and it is immensely popular!
<p>what grade are you in? there are thousands of experiments all schools should have.</p>
<p>whats the use of sand paper in this project</p>
<p>thanx james you are very helpful for me</p><p>thanx a lot</p>

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Bio: In my free time, I enjoy building/modifying/dismantling anything I can get my hands on. I am currently an engineering student at UCLA and ... More »
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