Downdraft

Downwash is the name for various air movements in meteorology and aviation .

use

meteorology

In meteorology, the term stands for different air movements depending on the context. In the lee of mountain slopes or on gently sloping terrain, it describes air flowing downhill. In the area of fronts , in shower clouds and thunderclouds, it describes falling winds. In a region, downdraft stands for a flow of air that brings emissions to someone. Z. B. in a region with predominantly westerly winds and a residential area is east of an industrial plant, it can be said that the residential area is in the downdraft of the industrial plant.

aviation

Downwash of a helicopter while hovering over the water

Alouette III helicopter of the Swiss Army: demonstration of a landing after dropping a smoke petard, here at Emmen airfield; the technology was suitable for assessing the turbulence of the wind on mountain flanks for landings in the mountains

In aviation downdraft called ( English downwash ) a technical downdraft as airplanes and helicopters of the wings or rotors in the generation of dynamic lift produced. In helicopters, this is generated by the rotating rotor blades and is very clearly perceptible to the environment during take-off and landing. The downwash can be used deliberately, for example to clear excessive amounts of snow from trees with a downwash flight . From the 1950s, the Kaman HH-43 Huskie was used as a rescue helicopter on US bases , which had the task of blowing the fire brigade and any injured persons away from the fire.

Also in air traffic, the wind turbulence behind a mountain ridge must always be observed when flying in mountains (see downwind in the lee of mountain slopes ). Even if a helicopter lands on a hilltop, it is to be expected that the correct approach against the wind will suddenly end up in an area in which there is a tailwind, which can be sufficient to cause a crash. The helicopters of the Swiss Air Force always carried smoke petards with them so that the pilot could throw a smoke petard in an overflight in unclear situations in order to be able to correctly assess the decisive wind conditions close to the ground for the subsequent approach. If the plane crashed on Biferten , such a downdraft might have been the reason for the crash, as the plane hit only three meters below a mountain ridge.

Motorsport

The technical term also appeared in racing. So it was for 1 Rules Formula from 2008 talking, a "CDG wing" ( English introduce "Centerline downwash generating wing" downwash generating center line wing). This should improve the slipstream for the following traffic in order to generate more overtaking opportunities or maneuvers and thus more tension in the race. However, this development was not used.

See also

• Updraft
• Down wind

Web links

Commons : Downwash  - collection of images, videos and audio files

Wiktionary: Abwind  - explanations of meanings, word origins, synonyms, translations

Individual evidence

1. ↑ Mike Tooley, Antonio Filippone, THG Megson, Michael V. Cook, PW Carpenter, EL Houghton, David Wyatt, Lloyd R. Jenkinson, Jim Marchman, Filippo De Florio, John Watkinson, Pini Gurfil, Howard D. Curtis: Aerospace Engineering Desk Reference , Verlag Butterworth-Heinemann, 2009, ISBN 9781856175760 , p. 939
2. ↑ Madeleine Kuhn-Baer: 50 years ago: tragic air accident in the deadly area ( memento from August 20, 2016 in the Internet Archive ). In: Glarner Woche, Glarus Süd edition , July 13, 2016, pp. 1–3.
3. ↑ article in Computer Science (Engl.)
4. ^ F1-Technical