Chevron (aerodynamics)

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Chevrons at a GE GEnx -Strahltriebwerk a Boeing 787 of Air India
Chevrons on both the nozzle and the nacelle

Chevrons are the sawtooth-shaped patterns on the trailing edge of the exhaust nozzle or the trailing edge of the nacelle of a jet engine ; on the trailing edge of rotor blades, this pattern is called the trailing edge crest. The sawtooth-shaped pattern leads to better mixing of air currents of different speeds.

aviation

In the case of the thrust nozzle, the pattern leads to a better mixing of the air layers between the hot and fast combustion gases and the cold and slower bypass flow or between this and the air flowing past the outside of the engine, which ultimately leads to a reduction in noise emissions.

It was initially thought that chevrons reduced the thrust. However, research by NASA in 1998 showed that the loss of thrust is less than 0.25%. DLR measurements in 2001 also showed that chevrons reduce noise emissions from an Airbus A319 engine by around 1 dB (A).

Wind turbine

Rotor blade with trailing edge comb for noise reduction

At the rotor blades of wind turbines there are different flow velocities on the suction and pressure sides, which lead to turbulence and a noise level at the trailing edge. The trailing edge comb reduces turbulence and noise emissions.

See also

Web links

Commons : Chevrons (jet engine nozzles)  - Collection of images, videos, and audio files

Individual evidence

  1. ↑ Chevron nozzles reduce noise on Lufthansa's Boeing 747-8 - Aerosieger.de - Das Fliegermagazin
  2. ↑ Evolution from 'Tabs' to 'Chevron Technology' - a Review ( Memento from November 20, 2012 in the Internet Archive ) (PDF)
  3. ↑ https://www.lufthansa.com/mediapool/pdf/87/media_773669987.pdf
  4. ↑ http://www.dlr.de/as/Portaldata/5/Resources/dokumente/abteilungen/abt_ts/Abschlussbericht_LFVK.pdf?page=116
  5. ↑ a b ENERCON wind energy converters trailing edge ridge. In: Technical Description. ENERCON GmbH, October 21, 2014, accessed on April 30, 2018 .