Pitting a CFD-Optimized Toroidal Propeller Against a Conventional One

Although we often think that we got certain aspects of aerodynamics pretty much licked at this point, details like the optimal shape of a propeller remains hotly debated, both in- …. Pitting a CFD-Optimized Toroidal Propeller Against a Conventional One. This also includes wilder designs like toroidal propellers that even after more than a hundred years are still mostly just being evaluated.

Recently [Neuronautics] took a shot at figuring out whether toroidal propellers even make sense. To do this, first an efficiency baseline was established using a conventional and highly optimized propeller. After scanning it in to get its exact geometry and running it through a computational fluid dynamics (CFD) simulation, the software spat out several about 73%.

This left figuring out an optimized shape for the toroidal propeller to pit against it. While you can absolutely brute-force the seventeen shape parameters being considered here and test them in CFD, this would take insanely long. The hack here is to use multiple reference frame (MRF) to drastically speed up the selection process, though even then it still took two months.