![]() (Kersti/CC BY-SA 3.0)Īdmitting that current technology to reduce airfoil noise has reached a “bottleneck,” Liu said, “The noise reduction capabilities of conventional saw tooth structures are limited, and some new non-smooth trailing-edge structures need to be proposed and developed to further tap the potential of bionic noise reduction. ![]() The fur-like down can be seen on the surface of the feather and has a similar function. These swirl the air so that no loud air noises are produced. ![]() The comb-shaped projections can be seen on the edge of the feather. The down absorbs frequencies measuring above 2,000 hertz, thus eliminating sounds that would alert owls’ hapless prey. The fluttery, downy feathers absorb any remaining in-flight noise. UNIQLO only uses sustainably sourced down and feathers from farms that seek to minimise their impact on wildfowl. With tattered feathers on the trailing edge of the wing and downy feathers on the legs and the rest of the wing, sound waves are broken up. It is possible that the feathers also shift the sound of the airflow to a higher frequency that most animals cannot hear.Īdditionally, owls’ secondary feathers have a soft fringe that reduces turbulence behind the wings. Why do raptors shed their downy feathers in the fall Watch the video to find out Remember, if you have an animal question you want answered in a future. Down is a fine thermal insulator and padding, used in goods such as jackets, bedding ( duvets and featherbeds ), pillows and sleeping bags. Powder down is a specialized type of down found only in a few groups of birds. Air is allowed to pass through them, eliminating sound. The down of birds is a layer of fine feathers found under the tougher exterior feathers. These serrations muffle the sound of the airflow, shifting the angle at which air flows. These beautiful coloured feathers will be perfect for putting finishing touch to costumes, masks and other decorative items. Copyright HarperCollins Publishers Definition of 'feather' feather (fe ) countable noun A bird's feathers are the soft covering on its body. See full entry for 'downy' Collins COBUILD Advanced Learner’s Dictionary. Unlike other birds, owls’ primary feathers are uniquely able to reduce turbulence over their wings because of their comb-like serrations. adjective usually ADJECTIVE noun Something that is downy is filled or covered with small soft feathers. Owls, like other birds, have various kinds of feathers. While older studies found that using serrated trailing edges could reduce the noise signatures of rotating machinery, the reduction of noise was not universal and depended on the final application. When the air flows back through an airfoil’s trailing edge, it radiates noise. When air flows over the back of an airfoil, it creates turbulence along its upper and lower surfaces. The shape of an owl’s wings changes continuously while the bird is in flight and chasing prey. A short-eared owl hunts at Elmley National Nature Reserve on Octoin London, England.
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