Flow Characteristics of Variant Models of Leading-Edge Serrations of Barn Owl Feathers

Understanding flow around the leading-edge serrations of barn owls is crucial for developing low-noise fluid machinery. The aim of the study is to analyze the unique flow characteristics of model serrations mimicking geometries of leading-edge serrations positioned at various points along the length of a barn owl’s feather. Thus, the physical system is tested in an experimental facility consisting of a channel flume with models of 3D serrations of second-order approximations, installed in the channel. The serration profiles were taken from defined geometries of serrations noted at 40% (near the base), 60%, and 80% (near the tip) of the vane length. Each model was connected to a base plate. Particle image velocimetry was used to obtain velocity measurements of the open-channel turbulent flow around each model. The results show flow outcomes proportional to geometry-induced blockages. Consequently, the tendency for flow resolution to the free stream conditions is in the order of 80%, 60%, and 40% model inserts. Each model also registers similar maximum turbulence intensities at the root of the serration. However, by far, the 80% model limits the wall-normal penetration distance of any self-generated turbulent effect to just about 30% of its length.