Hydrodynamic interactions are key in thrust-generation of hairy flagella

The flagellum in many predatory flagellates is equipped with rigid hairs, which reverse the direction of thrust to generate a feeding current. We have discovered novel mechanism for generation hairy flagella, fundamentally different from slender body theory governing smooth flagella. show that generated at crests flagellar wave, thanks key role hydrodynamic interactions among effectively functioning like sheet. suggests optimal should be long and curvy, consistent diverse designs flagella observed nature.