Random Engineering, Physics, ..., Concepts and Ideas

Windy_Skies · July 17, 2020, 2:05pm

https://www.reddit.com/r/Fusion360/comments/hsv3g1/airfoil_tools_for_fusion_360_new_addin/

Some interesting stuff in the linked Autodesk forum post:

I’ve done some meta-analysis on the results of my particle-swarm optimizer which myself and other die-hard optimization freaks might appreciate knowing - as you may know, I’ve had 180 CPU cores across many (expensive) machines working full-time on this since Covid-19 imprisoned me at home (and also fewer cores, not always full-time, since 2012 too). I optimized for Reynolds Numbers from 50 to 100,000,000 - so I am now able to plot the CL/CD for all of the best-performing foils that my code has “birthed” (it’s a genetic optimizer):-

Which basically points to there being a “sweet spot” at around Re 7,000,000. What this basically means in laymans terms, is that if you are (like me) working on designing an underwater turbine to harness ocean currents, you’ll want a root chord length of about 3 meters designed to turn at about 4 knots to extract the most possible energy with the least annoying torque-effect from the current.

Or, more generally, you want “longer chords” and “faster speeds” whenever you can, to try and get that Reynolds number up as much as practical, since you can see in the chart - the performance efficiency line just gets better and better as you go higher (maxing out from Re 7M).