Can Air be Made Visible?

Specifically so that we can see what it's doing. Why? Because as a glider pilot it is good to know where the upward flowing currents of air are.

The first and simplest answer is yes, all you have to do is mix something in it and voila! Smoke, water vapor or steam, dried leaves and corn shucks, anything floating in the air will tell you something about what the air is doing around you. For a soaring pilot, that includes all of the above and other flying creatures. Even better than a vario, which tells a pilot what the air is doing where he is now, visible cues from other things tell him what the air is doing where he is going or conversely where not to go.

The best example in soaring is another glider or perhaps a soaring bird. An experienced pilot in a thermal with one or more others will watch them carefully. Assuming everyone is turning in the same direction as is proper, he will use the relative motion of the other to judge his own path. If he is climbing relative to the other, then he will tighten up his turn to stay where he is rather than follow into what is obviously less lift. If on the other hand, the other is out climbing him, he will turn toward the other to go toward the better lift.

And again, anything visible in the air that indicates the presence of lift is helpful. Circling birds, leaves and of course those beautiful cumulus clouds that form as thermals reach the dew point altitude and condensed water droplets appear are visible signs of lift. But all that is stuff that is already there to see. I recently read of some scientists who used tiny helium filled soap bubbles in a wind tunnel apparatus to study airflow on bird wings instead of smoke. Easier on the birds.

But what about seeing the air more directly? We know that air of different densities has different refractive indexes. This is responsible for the shimmering mirage effect seen on hot highways and other surfaces. The twinkle of stars seen from the ground at night is due to the light passing through our atmosphere that is made up of layers of differing densities and moving constantly with waves , currents and eddies. Interestingly, astronomers have been able to use software on the captured images to filter out much of the 'twinkle' for clearer views of our neighbors in space.

So, we know there are different physical properties of air at different temperatures that are measurable. And temperature implies that the matter of air molecules is in fact radiating that heat energy as everything else made of matter is. We also know that warmer air tends to rise relative to cooler air. That is the whole basis of the thermal as we soaring pilots know it. Another thing we know is that there exists devices known as night vision glasses that take infrared radiation and make it visible. There are also devices that look for this infrared radiation and guide missiles based on it.

That brings me to the story I heard a few weeks ago while talking to my friend Clark. As he told it, he was down near Atlanta, GA at a place called Stone Mountain. He was up on the rock where he noticed some men working with some electronic equipment. On asking what they were doing, he was told that they worked for a large aerospace company and were on a project to do with heat seeking or cruise missiles, I don't remember which. But they said they were trying to find thermals remotely. Apparently, thermals were causing problems for the missiles and if they could see them, they could avoid them. Clark said cool! When do you think we can have goggles or glasses based on this work. Uh, well we don't... Not on our schedule... Don't hold your breath.

But what a boon for aviation in general. Anyone who has ever ridden in an airliner knows what it feels like to hit turbulence at 500 miles per hour. Potholes in the sky and sometimes, the pilot will come on and war everyone to buckle up. He didn't see them but he was told by other planes that it was coming. Imagine the toll those potholes take on the airframes of those jets year after year. Although, I don't think that jetliners would be dodging them even if they could see them. But other smaller general aviation aircraft could dodge what they could see coming for much smoother rides.

Looking at the problem, it seems that what is needed is a way to receive the infrared heat energy on a detector, filter out the data from everything that is not air, i.e. background, earth, trees roads, buildings, etc. and present the data graphically overlaying the visual. In an ideal form, I imagine being able to scan the sky and see outlined in red, columns and bubbles of warmer air. The intensity of the red would indicate the strength or relative warmth of that area of the sky.

There are days like last week when I was watching those cloud streets when lift was everywhere. Free energy for the taking if you could only see it.

What do you think?

Also posted at Daedelus' Notebook

 

Log in or Sign up to hide all adverts.

Seems this 'Science' forum is infested with nonscientific thinkers.

 

Log in or Sign up to hide all adverts.

Doppler radar

Super refractionTemperature inversions often form near the ground, for instance by air cooling at night while remaining warm aloft. As the index of refraction of air decreases faster than normal the radar beam bends toward the ground instead of continuing upward. Eventually, it will hit the ground and be reflected back toward the radar. The processing program will then wrongly place the return echoes at the height and distance it would have been in normal conditions.

WIKI

 

Log in or Sign up to hide all adverts.

You can liquify air , and it will be very visible

 

And that contributes to a solution to the objective how?

 

. . . ask those folks in Arizona (re: recent zero-visibility dust storms) about making air visible!

 

How about http://en.wikipedia.org/wiki/Schlieren_photography

 

As a soaring pilot of many years experience, I think I have a pretty good mental image of what thermals would look like. And there are similar phenomena that are readily visible. Dust devils for instance are in fact the base of particularly vigorous thermals and the dust and trash they suck up make them visible as is the case with tornadoes and other cyclonic wind patterns. But such strong disturbances are too dangerous obviously.

I can say that the flow of bubbles from the bottom of a boiling pot, or the smoke column from a leaf fire are good visual references. In fact smoke from fires often gets entrained in thermals giving them a bit of visibility.

If the more gentile* flows of air were locatable, that would be what I'm looking for. As it is, gliders must rely on knowledge and experience to find those invisible stairways to heaven. With a visible road map, that free energy would be available.

*Upward flows of from 150 feet per minute to over 1500 feet per minute and more are still gentile compared to the 'more vigorous' kind and are usable currents for soaring craft.

 

Yes and yes. The "tech is there" idea can be applied to a lot of cool ideas. And as we know, when the need or desire is there things can get made very small. We now walk around with stuff in our pockets that used to fill whole rooms.

Thanks for the LIDAR reference, I'll look further into that.

 

Either you can add visible particles to the air and watch them (dust/clouds), or you can try to change the properties of air itself to make it visible, or you can detect the radiation coming from the air to determine changes in volume/shape of air masses.

The "sunglasses that let you remotely detect air columns" would be the latter, and the least likely to have environmentally damaging side effects.

Get a thermal imaging camera, and start working on intelligent false-coloration of the air mass patterns!\
http://www.flir.com/cvs/cores/uncooled/products/tau/tau640/

http://www.bullard.com/V3/products/...ning/articles/Interpreting_Thermal_Images.php

 

I've thought of having a container of reflective 'dust' that could be released when encountering a thermal to mark it, but again that only tells you what the air where you are is doing, not where your next thermal is.

Don't see this as practical. Might as well wish for magic pixies to show the way.

This is the idea. Can we discriminate between air masses of different temperature/density?

Just what I want for Xmas

Good links, thanks.