Compartmentalized

The debate of whether to make an open or closed-circuit wind tunnel has come to a close. The winner is: both? In the interests of convenience, I'm going to make the various components of the tunnel highly separable. I have a collar mechanism in mind, and will try to put the information up on the website, sometime tomorrow. For the sake of making the engineering easy, I'm going to try to have two primary sizes: test-section, pre-constriction (also known as small and large).

If you model the wind tunnel as a test section, followed by a really long diffuser, then a contraction, then the axial fan would, usually, go somewhere in the middle of the diffuser. In my case, diffusers are complicated to build, and so I'm going to try to make the diffuser fit between the test-section and the second corner. Doing so would allow me to hide all of the intermediate sizes in three sections (first diffuser section, first corner, second diffuser section). All other collars would be either small or large.

I'll start designing tomorrow, and start stubbing out a python file to perform the pressure-drop estimates, etc., and we'll see how feasible this plan is.

Design Order

I have, now, had a chance to read a decent amount in the wind-tunnel design book (~50 pages). The equations and methods used in the wind-tunnel book are starting to click with those employed in the introduction-to-flight book, cementing my general aerodynamic understanding. My parents and brother will be arriving in just over three weeks, and I am hoping to have a component designed and ready for construction by the time they all arrive -- thus the design-order question.

The test-section is seeming to be the most logical thing to start with, as, for the initial version, I won't require the ability to take precise measurements (provided I have, at the very least, a good idea of how to amend that shortcoming later). The next component that I would foresee us working on would be the diffuser, immediately proceeding the test-section, as doing so does not require knowledge of the target size.

Partners In Crime

Two of my swing-dancing buddies might be helping out, once construction begins. Autumn has done a great deal of wood-working in the past, and Nick is a fabricator by trade.

Moving On

It does not appear as though construction of a high-reynolds-number wind-tunnel is going to happen. The wind-tunnel testing book states pretty clearly that small tunnels like this one will not reach reynolds numbers that even approach reality. This project is a bit of a hail-mary as-is, so I shouldn't be trying to push the edges of too many envelopes at once.