Strange phenomina

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Sines
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Strange phenomina

Post by Sines »

Moments after this plane left it's rainbow trail behind this developed. Around the cockpit section and wingtip and even as it seems in front of the plane some tiny white swirls appeared very briefly about during ten seconds off and on. Anyone knows what this is called and why it happens?
Thanks, Jos
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aviodromefriend
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Re: Strange phenomina

Post by aviodromefriend »

Can it be it is some kind of condensation?

I know there is some more common description for it, but it just escapes me at the moment. A bit like what you sometimes see on photos from airshows at the upper parts of fighterwings. I just think about that one as it seems to happen on places with some lower pressure.
De Zamboni heeft kramp in zijn achterwiel
Jan Maarten Smeets, Heerenveen 31 oktober 2009
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Flyboy
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Re: Strange phenomina

Post by Flyboy »

On areas of low static pressure (at the locations the velocity of the air is increased resulting in a higher dynamic pressure and thus a lower static pressure) the air can contain less water (moist). The water is forced out of the spaces between the air molecules and becomes visible as a mist / vapour. A bit later when the pressure is equalised the vapour is dissolved again in the air.

The areas of higher dynamic pressure may be the nosecone and over the wing surfaces and their trailing vortexes.

Also good visible with the wings with flaperons extended of an F-18: this is a 1G situation

The other example aviodromefriend mentioned is in a high G situation such as with the F-15: a horizontal turn results in high G: The wings need to provide more lift (by increasing the angle of attack) and thus an lower static pressure than with the nornal 1G flight: the vortex is created at the wingtip where the high static pressure under the wing flows to the low static pressure over the wing.

Normal contrails behind aircraft excist because the high amount of hot watervapour (due to combustion of fuel: C6H14 + 13O2= 6CO2 + 7H2O) is dumped in the cold air. The air cannot dissolve the water at once so a contrail emergers until the water is dissolved in the air. This has nothing to do with local pressure differences.
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aviodromefriend
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Re: Strange phenomina

Post by aviodromefriend »

Flyboy wrote:The other example aviodromefriend mentioned
No, I meant the thing you described first. Can't see any of that second phenomina you try to put in my shoes in the picture posted by the OP.
De Zamboni heeft kramp in zijn achterwiel
Jan Maarten Smeets, Heerenveen 31 oktober 2009
Sines
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Re: Strange phenomina

Post by Sines »

Thanks for explaning. Did anyone else ever notice these swirls with airliners in these Conditions? i must admit iT almost escaped my attention because mostly i look behind the plane. also did anyone notiice these swirls from within an airliner?
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