Getting in the Wind Tunnel: Design

Dear Fellow Basement Scientists,

Ever wonder why textbooks are so long? Well, I figured it out! Its because there is a lot of information out there to learn and it takes quite a few pieces of paper to fit it all. Well, this blog post is a little longer, though not quite textbook length, because there is a lot of information required in applying that textbook knowledge to building our wind tunnel.

Its time for another day in the lab (basement). Lets review our situation: We built the tunnel, legs for the tunnel, and finished the bell mouth including the honeycomb. Before we go on to the fan and diffuser, we can’t forget the minor detail of accessing the inside of the wind tunnel once it’s built. We must have an opening so we can put our specimens into the wind tunnel. Otherwise we would have a very fancy and long fan. I was hoping for more than that.

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Wind Tunnel Honeycomb

Dear Fellow Basement Scientists,

Here we are, placing the last finishing touches on the entrance to the wind tunnel. This is pretty exciting! We are discussing today what is known at the honeycomb. I very briefly mentioned this part of the project in Wind Tunnel Design Overview, but now we will discuss its purpose and construction.

So, if you remember, the purpose of the bell mouth entrance is to reduce all the whirly-twirly turbulence coming into the test section. Reducing this turbulence increases the accuracy and consistency of lift and drag measurements. Well, believe it or not, despite all our valiant efforts on the bell mouth, there is still turbulence in the flow. Bummer! Well, no worries because we can simply install a honeycomb to help us out (as a note, there is always some turbulence in this flow, we are just reducing it as much as possible). A honeycomb consists of lots of little tubes. These tubes kill turbulence because there can’t be big swirls in a little tube.  Here is a highly technical drawing laying out the details of this complicated phenomenon:

Honeycomb Detail

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Project: Wind Tunnel

One night laying in bed, I often can’t fall asleep because I am thinking about mechanical things, I was thinking about wing designs. Many PhDs, professors, and companies are trying to think of innovative aircraft design for increased performance. I had some interesting ideas which I had never seen before and wondered if they had any merit.  I decided I wanted to throw my hat in the ring. The only way to determine if they are any good is simulations in a computer program or a wind tunnel, for me then, wind tunnel it is.

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