High-angle helix helps bacteria swim

A really interesting fluid dynamics problem

Locomotion is a different proposition at the cellular scale. A bacterium — this is a helical leptospira — that is swimming through water “would be like us trying to swim in tar.” Some microorganisms swim with helical flagella, but how?

It’s counterintuitive but true: Some microorganisms that use flagella for locomotion are able to swim faster in gel-like fluids such as mucus. Research engineers at Brown University have figured out why. It's the angle of the coil that matters. Findings are reported in Physical Review Letters.