JaXanim wrote:
For several weeks now, our regional newspaper has published letters to the editor on the subject of aircraft vapour trails and how they are formed.
Many readers have submitted their observations about these fascinating phenomena and have put forward their hypotheses as to the physics involved. Many people have said that the trails are created by the jet engines. However, several writers have dismissed that idea. Instead, they assert with apparent authority, that the trails are caused by the precipitation of water vapour in low pressure vortices at the wingtips of planes.
Anyone care to comment on the physics of vapour trails?
Cheers,
JaX
Actually it's both. The Vapour trails you see from large Jet airliners are from the exhaust water, heat, soot and NOX etc from the engines.
But at the wing tip you have a point where high pressure under the wing "leaks" up around the wing tip to the low pressure above the wing, commercial aeroplanes have Winglets (those little vertical fins on the wing tips) to top this, and as it leaks up it forms a vortex. These vortices heat and compress the air and it mixes with the cool air around it, water condenses out.. etc...
You will only really see a wintip vortex on a small military jet, usually when it in a high G turn and there is a lot of energy in the vortex.
