comments:
After some research it sounds like the best structure to use for "straightening" out air flow is a honeycomb. I found a honeycomb mesh on amazon like this. The key is how small the holes are and getting some length.https://www.amazon.com/Diycoming-Honeycomb-300x300x15mm-Ultra-Lightweight-Repairing/dp/B0F1C8LBCB/ref=sr_1_6?crid=JQG88CS5TWBP&dib=eyJ2IjoiMSJ9.qJKTPFfWIJnQFKBueGQnooq8myu9FqZCr3pWsXUlou47WJLboDwXwMLeCEPYZIz-rYWcMWA-am-EXJxgDrJiPsPoykNDTipQAZhA4kiyduELpx6nS5_pigQV3ElqCQECFConIqAdk3QmcSFxhoIevORYqIoSQgLC1KncIwmGAal0-RX56eRYrVtozRKnsyG-MerBB6q1umf1634JHdTGupaxWPVvSevOIdcfikTiKaAk7vRFl2YzN1NgaFfFRcSHRQRnBxqgZ1QyUJb6ffoxQgkBQpr7rcBf_oRQ8aKWvlc.IEFl8zKHYJabdXOuXIo882E7NFidEM1mojh6tof7WwQ&dib_tag=se&keywords=honeycomb%2Bcell&qid=1781191838&sprefix=honeycomb%2Bcel%2Caps%2C236&sr=8-6&th=1 Then you could layer a fine screen mesh outside of that and then a foam filter. So it would be fan -> duct -> honey comb filter -> screen filter -> foam filter. The only issue is this would require some testing, but the parts are all cheap enough, minus the fan and hepa filter (but you only have to buy those once).