Say you want to make a filter or a catalyst and you use incompressible, cylindrical fibres. Even when the fibres are packed together as closely as possible, there will be a guaranteed minimum volume between them (through which a fluid might percolate).
(If you use square section fibres, they might align, in the worst case, so as to give effectively zero volume between them).
Today’s invention is to use fibres for your device which are regular octagons in cross section.
These provide a minimum flow volume -which is way better than those with square cross section and just a little bit better than purely cylindrical fibres.
Octagonal ones may well offer the best possible minimum porosity, but this hasn’t been proven yet.
In an application which is super sensitive to the pressure drop through the system, this small difference in flow space might be significant.
