  This work describes a novel mechanism of laminar flow control of a backward
swept wing with a comb-like leading edge device. It is inspired by the
leading-edge comb on owl feathers and the special design of its barbs,
resembling a cascade of complex 3D-curved thin finlets. The details of the
geometry of the barbs from an owl feather were used to design a generic model
of the comb for experimental and numerical flow studies with the comb attached
to the leading edge of a flat plate. Examination was carried out at different
sweep angles, because life animal clearly show the backward sweep of the wing
during gliding and flapping. The results demonstrate a flow turning effect in
the boundary layer inboards, which extends along the chord over distances of
multiples of the barb lengths. The inboard flow-turning effect described here,
thus, counter-acts the outboard directed cross-span flow typically appearing
for backward swept wings. From recent theoretical studies on a swept wing, such
a way of turning the flow in the boundary layer is known to attenuate crossflow
instabilities and delay transition. A comparison of the comb-induced cross-span
velocity profiles with those proven to delay transition in theory shows
excellent agreement, which supports the laminar flow control hypothesis. Thus,
the observed effect is expected to delay transition in owl flight, contributing
to a more silent flight
