Debunked: Look-up.org.uk's Chemtrail "Missing Link" [hybrid contrails]

Mick West

Administrator
Staff member
The photo does not show much in the way of crow instability, except for the little wiggle at the end (the far right).

The tubes/rings are a hybrid contrail - portions of an exhaust contrail that have been made more persistent by the lower pressure conditions in the center of the wake vortices. The irregularities are just variation in pressure from eddy turbulence, greatly exaggerated by perspective, so they look like rings. This contrail would fade away in a few seconds - the patchy nature of the trail indicating marginal conditions.

This videos shows the entire formation process:

Here's another example, note the forced perspective again, and the fact the they don't last very long, indicating marginal conditions.


You can see the formation of these rings in a much shorter-lived aerodynamic contrail:



Source: http://theaviationist.com/2013/12/02/charles-de-gaulle-slowmotion/

When the contrails last longer, the eddy turbulence gives rise to the bumps within hybrid contrails, and/or the "pendules" on the larger exhaust contrails.

Some great animations on the various fluid mechanics, here:
http://flowgallery.stanford.edu/research.html

More here:
http://contrailscience.com/hybrid-contrails-a-new-classification/
https://www.metabunk.org/threads/crow-instability-hybrid-contrails-and-pendules.1571/
https://www.metabunk.org/threads/donut-chemtrail-why-pendules-and-crow-instability.1220/
https://www.metabunk.org/threads/hy...on-of-symmetric-and-asymmetric-contrails.929/

It's dark because it's in shadow.
 
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Mick West

Administrator
Staff member
The carrier landing is here, in better slow motion (I've just extracted the relevant bits)


You can see very clearly that it starts out as a solid tube, and that some bits of it simply persist longer than others.
 
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Hama Neggs

Senior Member.
The carrier landing is here, in better slow motion (I've just extracted the relevant bits)


You can see very clearly that it starts out as a solid tube, and that some bits of it simply persist longer than others.

Or does centrifugal force throw the moisture's mass outward to form the rings?
 

Ross Marsden

Senior Member.
[snip]

Some great animations on the various fluid mechanics, here:
http://flowgallery.stanford.edu/research.html

[snip]
Very interesting. So the puffy structures, we have been calling "pendules", are actually a manifestation of the Crow instability. The time scale is about right.

I have seen these pendules referred to as "evidence of pump technology used to disperse the aerosol particulates", to paraphrase roughly.
 

Eden

New Member
"We think we know what it is" states the author of the image in the OP. This is not the first time that chemtrail conspiracy theorists have sited this phenomena as evidence of chemical dispersion.

The rings seen emanating from the exhaust are known as Shock Diamonds:

Shock diamonds (also known as Mach diamonds, Mach disks, Mach rings, doughnut tails or thrust diamonds) are a formation of standing wave patterns that appears in the supersonicexhaust plume of an aerospace propulsion system, such as a supersonic jet engine, rocket, ramjet, or scramjet, when it is operated in an atmosphere. The diamonds are formed from a complex flow field and are visible due to the ignition of excess fuel. Mach diamonds (or disks) are named for Ernst Mach, the physicist who first described them.
Content from External Source
At each shock diamond, the flow becomes compressed enough that it expands outward in a set of expansion waves called the expansion fan. Eventually the flow expands enough so that its pressure is again below ambient, at which point the expansion fan reflects off the contact discontinuity (the outer edge of the flow). The reflected waves, called the compression fan, cause the flow to compress.[2] If the compression fan is strong enough, another oblique shock wave will form, creating a second shock diamond. The pattern of disks would repeat indefinitely if the gases were ideal and frictionless,[2] however, turbulent shear at the contact discontinuity causes the wave pattern to dissipate with distance.[4]
Content from External Source
This phenomena is not restricted to man-made devices and can be seen in the dispersal trail left by extremely powerful quasar as they spew enormous plumes of plasma across vast distances (often thousands of light years) of space.
 

solrey

Senior Member.
"We think we know what it is" states the author of the image in the OP. This is not the first time that chemtrail conspiracy theorists have sited this phenomena as evidence of chemical dispersion.

The rings seen emanating from the exhaust are known as Shock Diamonds:

Shock diamonds (also known as Mach diamonds, Mach disks, Mach rings, doughnut tails or thrust diamonds) are a formation of standing wave patterns that appears in the supersonicexhaust plume of an aerospace propulsion system, such as a supersonic jet engine, rocket, ramjet, or scramjet, when it is operated in an atmosphere. The diamonds are formed from a complex flow field and are visible due to the ignition of excess fuel. Mach diamonds (or disks) are named for Ernst Mach, the physicist who first described them.
Content from External Source
At each shock diamond, the flow becomes compressed enough that it expands outward in a set of expansion waves called the expansion fan. Eventually the flow expands enough so that its pressure is again below ambient, at which point the expansion fan reflects off the contact discontinuity (the outer edge of the flow). The reflected waves, called the compression fan, cause the flow to compress.[2] If the compression fan is strong enough, another oblique shock wave will form, creating a second shock diamond. The pattern of disks would repeat indefinitely if the gases were ideal and frictionless,[2] however, turbulent shear at the contact discontinuity causes the wave pattern to dissipate with distance.[4]
Content from External Source
This phenomena is not restricted to man-made devices and can be seen in the dispersal trail left by extremely powerful quasar as they spew enormous plumes of plasma across vast distances (often thousands of light years) of space.

The plane is probably not a supersonic jet anyways, and shock diamonds form immediately behind the exhaust, are evenly spaced and dissipate with distance while what we see in the OP is pretty much the opposite of that. The morphology of the contrail matches what would be expected of exhaust contrails becoming entrained downstream in the wake vortices off the wing tips.

Here's a vid of aerodynamic wake vortices behind a 777 while landing.


Along with others, I'm also curious about what the folks involved with "Look-Up" think it is.
 

Trigger Hippie

Senior Member.
Ya, I'm not too sure about that shock diamond hypothesis.

In one well-known example of this fact, the Crow Instability causes the vortices to develop symmetric sinusoidal oscillations and eventually to merge and form vortex rings behind the jet. This instability can be triggered by turbulence in the surrounding air or by local variation in air temperature or density, which may itself be the result of the stratification of the atmosphere. When the contrails are visible and strong, it is possible to see the white streaks become wavy and then leave rings floating high in the sky, like smoke rings from a giant cigar. -- Scientific American
Content from External Source
 

Eden

New Member
I stand corrected. After reviewing Micks animation of the carrier landing I see that the circular trails are originating from the wing tip and not from the aircraft engine.

As for the image in the OP, after looking over hundreds of photos of contrails left by aircraft engines of varying type, I cannot help but to feel as though the image has in some way or another been doctored to give the contrail a "dirty" appearance.
 

Mick West

Administrator
Staff member
As for the image in the OP, after looking over hundreds of photos of contrails left by aircraft engines of varying type, I cannot help but to feel as though the image has in some way or another been doctored to give the contrail a "dirty" appearance.

No, it's just the lighting and exposure. It's not in direct sun. You need to compare it just to photos of contrails taken from planes at similar levels or above the contrail. Like here, at 0:39 onwards



Or here at 0:26 (and several others - excellent compilation, if a bit low res)
 

Mick West

Administrator
Staff member
And even if it was, it's not going to be landing at 800 mph. :) Carrier jets land around 160mph air speed.

Correction after looking at the above - it's the exhaust that's supersonic, not necessarily the plane, so you could theoretically see them when landing.



(The above is takeoff, but planes land on carriers with considerable thrust, in case they miss the hook, and have to take off again - maybe not this much though)

Of course, in the carrier image the aerodynamic trails are coming from the wings. However it would be interesting to see what effect a shock diamond would have on an exhaust contrail. I'd suspect not much, as there would be plenty if turbulence to mix it a few ms later.
 

Eden

New Member
...However it would be interesting to see what effect a shock diamond would have on an exhaust contrail. I'd suspect not much, as there would be plenty if turbulence to mix it a few ms later.

My thoughts exactly. I looked into it, but couldn't find anything concrete apart from scramjet contrails exhibiting the knot-like formation at regular intervals along the contrail plume. Even in that case, I couldn't find anything that conclusively demonstrated the said formation as being a product of the aircraft exhaust.
 

Mick West

Administrator
Staff member
Very interesting. So the puffy structures, we have been calling "pendules", are actually a manifestation of the Crow instability. The time scale is about right.

I have seen these pendules referred to as "evidence of pump technology used to disperse the aerosol particulates", to paraphrase roughly.

I don't think the pendules come from crown instability - at least not the initial pendules. Crows instability refers to the twisting of the wake vortices, which is actually on a longer time scale than the pendules.

I took this series of three photos a few seconds apart.


The crow instability is what is making the hybrid portion of the contrail more distorted, with a wavelength of about quarter of the frame. The pendules have a wavelength of about 1/40th of the frame, and coincide somewhat with the thicker portions of the hybrid contrails, which will manifest as "smoke rings".

This is the plane at around that time:


And a minute later.

The angle is sharper now, so you can see the "rings" in the upper left:
 
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