Thread Tools
This thread is privately moderated by phil alvirez, who may elect to delete unwanted replies.
Jan 27, 2016, 04:10 AM
Registered User
Thread OP
Data

soaring: waves and stranger things: corridors


i want to talk about another source for lift, that i have learned recently. it is a narrow band across the wind.
more specifically:
corridor: a stationary invisible narrow band across the wind, that generates lift.
this happens to me at a flat field with no elevations in sight (the only obstacle is a row of trees), located at 5km from a large lake. there is no wind blowing at the band mentioned; it is clear air all around; the invisible band does not drift (stationary for a long time). i know is there because the vario sends beeps that let me pinpoint its location; the wind does not penetrate it, and the band generates lift; i know this because i can keep my plane at that level forever. i have to keep the plane doing s turns within it to stay on the lift. if i turn the plane across it (facing the wind that is found below and above) the plane flies away of the band and sinks. the area is a narrow band across the wind (but wide enough to let my 2 meters sailplanes do full turns) that blows down here, and is present only at certain level (some 200 meters). ahead, behind, and below it, there is wind and the plane sinks no matter which way i turn, but drifts with the wind. and above, there is wind and sometimes i catch a thermal and drift with the wind.
i have been using 'wave' as it runs across the wind, to diferentiate it from 'streets', that run along the wind, but maybe this makes things confusing, as waves are generated near elevations.
at the end of the day, maybe 'corridor'can define it better.

after much thinking, getting help, finding articles on the matter of weather, and more thinking, i think now i know what is happening in the situation i find myself in this field.
it is based on a front that happens due to the proximity of a large lake effect after all.
see these articles that sumarize the reasons:
http://soaringcafe.com/2012/07/weath...-breeze-front/
http://www.weatherjackwx.co.uk/tutor...20breezes.html
http://web.science.mq.edu.au/~cassid...nvergence.html
(other interesting comments from: http://ozreport.com/data/WhyMicroliftSoaring.pdf
" Phenomena related to the discontinuity of large air masses (cold fronts, sea-breeze fronts,…) are the source of up-currents often extending over great distances and moving with respect to the ground although relatively independent of the terrain characteristics".
and then: ..."The exploitation of these waves, called standing waves because of their stationary position with respect to the ground, ... " )

wind from the lake meets air at the ground and the temperature differential causes the air at the ground to go up, in this case creating sort of a wave, but still based on a lake effect, or a front.
whatever you may call it.
of special value is this comment found at the end of the 1st article: Here’s a reply from author Dan Gudgel: “The answer, I believe, lies in the fact that the warmer air side is simply being “lifted” into the atmosphere where the cool air side is coming in “underneath” and therefore has some mechanical turbulence properties in conjunction with its movement over the surface and terrain.”
if any1 has something to add, please bring it.
and thank you very much all who has contributed (especially jbeanelliott).
Last edited by phil alvirez; Apr 11, 2016 at 02:40 PM.
Sign up now
to remove ads between posts


Quick Reply
Message:
Thread Tools