Aerodynamic performance of a single primary flight feather from a Jackdaw (Corvus monedula)

Birds have been flying for millions of years, yet little is known about how each feather contributes to a bird’s aerodynamic prowess. The outer feathers of a Jackdaw (Corvus monedula) wing are complex structures which can split from the rest wing into a slotted configuration, making each feather function like a separate airfoil. Using computational fluid dynamic simulations, these feathers are investigated to determine how the profile shape and microstructures of the feather affect aerodynamic performance at Reynolds number of 7000. The feather has structures, shaft and barbs, which extend into the air flow, which at first glance may appear to have negative effects on performance, however the findings demonstrate that there is no negative effect on lift. Whilst lift is favored, drag is not and the characteristic aerodynamic response are more like that of a dragonfly wing than airfoils and plates. The feather response to the aerodynamic forces is a pitch down rotation around the shaft, which is balanced by the feather morphology. All in all, suggesting a tradeoff of optimal functionality between other functions besides aerodynamic functions, as well as a passive pitch control mechanism which could be of interest when designing wind turbines or micro air vehicles.