Multi port Helix testing Sound for Airflow

thingiverse

I remembered an article from 2019 (and found it again) about Boston University Engeering that had developed and tested a sound reducing device that had no moving parts. https://www.bu.edu/articles/2019/making-the-world-a-lot-quieter/ Their device was made out of metamaterials (which I do not have) but they printed the part with a 3D printer. It may also be possible that their metamaterial is printed with some sort of miniature reflective design (which I did not try to emulate). I did some 'tinkering' and measurements on my 2013 Ford Focus exhaust, which isn't loud at all, and printed this to test. I used TinkerCad and created the part for my 2 inch ID exhaust. I don't think the article gave precise specs but I saw it basically as a cylinder with helixes created through it --- six. I actually figured out how to make a helix space in Tinkercad and got it all correct on my first print (aside from a failed print). I was able to blow air through each single helix (about one and a half turns). It also fit into my exhaust, however, I couldn't verify any sound reduction as my exhaust is quiet. It had been so long since I printed anything however, and getting this design correct (afaik) and having it fit my exhaust --- well, I was just happy with it. Without testing it in more detail, I doubt it works any where near as well as BU's device, if at all. Sharing with Thingiverse however. Enjoy