If you work in, or have a strong interest in engineering, it’s a good bet that at some point you’ve seen and admired wind tunnel testing. One might reasonably assume that such testing is undertaken by well-funded scientists in military or civilian labs. However, Mark Waller's build shows it’s possible to make your own miniature version.
Waller’s tunnel extends a few feet across a desktop, and sucks air in via a centrifugal fan at the rear of the chamber. An arrangement of tubes are implemented in front of the fan to ensure its rotation doesn’t affect the airflow.
On the other side, air enters a gently sloping venturi section, then flows through a matrix of drinking straws to produce laminar flow. Between the device's front and back air direction, the setup creates smooth flowing air — perfect for testing airfoils or other objects in the rectangular tunnel.
With air flowing and the object-under-test inside, smoke is injected via an e-cigarette using an aquarium pump, split up with five individual tubes. Windspeed can be adjusted from the control box, and the object under test can be turned as needed during the process.
Smoke patters are observed through a clear section on the side, along with internal lighting. The resulting photos, as seen toward the end of the clip, are quite stunning.