Wind Farm Wakes

[DamonHD]

http://withouthotair.blogspot.com/2010/01/wind-farm-wakes.html

The air must have been super-saturated with moisture: very interesting!

Rgds

Damon

[TomW]

HD;

That is so interesting. Probably means another bit of material for the anti wind minority arsenel. Changing weather patterns and all that.

Cool photo nonetheless.

Tom

[DamonHD]

I expect that the additional mixing downwind does have some noticeable effects, though the only problem I'd previously heard of was apparently in the reverse direction, ie in reduced dew formation from moist air that would otherwise hug the ground, causing crops to be drier than previously.

There has to be some effect, but my feeling is that it must be effectively noise most of the time...

Rgds

Damon

[fabricator]

That pic needs some wakes photo shopped in at the tower bases, it would look like the turbines were really traveling.

[electrondady1]

as mentioned in the comments of that article,

it's possible that that is a photo shopped image.

 has any one ever seen any similar phenomenon.

[TomW]

1;

Sadly, that is a good point. A savvy graphics manipulator can make anything look real to the nekid eye!

Never seen anything like it not produced by a jet aircraft [con trails].

Still a cool photo.

Tom

[electrondady1]

oh yea, i saved it too!

[ghurd]

While I think it may be possible, I think the photo is faked.

Looks like the 'fog' is concentrated near the center of the blades and spreads out.

I believe if it happens, it would occur near the tips first.

I think it would look more like this pic,

and I'd guess this is a fake too, because vortices do not look distorted by plane's wing.  Maybe it's just the angle...

http://en.wikipedia.org/wiki/File:C27J_Spartan.jpg

I have seen wing tip votices on a Beaver going 85MPH in high humidity, but they don't last far past the trailing edge.  A couple inches.

G-

[DamonHD]

If you read the whole comment train, it seems that the photo is real, even if a rather rare occurrence...

Rgds

Damon

[SparWeb]

I for one believe it is possible.  When the air is close to the dew point, it often doesn't take much disturbance to provoke condensation.  The sudden pressure drop won't likely cause it, but the gradual pressure recovery in the wake could.  

There is a fog already visible on the water's surface, caused by moist air cooled by the water below.  There is a gradient of increasing temperature with increasing height, but this gradient is "stirred up" by the blade wakes.  The condition where the fog can form at the sea surface is recreated in the wake of the WT because the cold air is now brought up into it.

[Capt Slog]

I've seen this effect from the spoilers/wings fitted to racing cars in F1.  It was some years ago in a race I was watching on TV, the air must have been just on the dew point(?).

As mentioned by someone else in the thread, you'd expect to see some trail at the blade tips.  Now THAT would have been a really cool photo, because you'd be seeing a triple helix going away from the turbine.

.

[bob golding]

yes i have seem this on the wings of  top fuel dragsters. or at least a slomo tv image. very similar. but  you can some wonderful things with photoshop and  plenty of time. cant really see why anyone would bother to try to pretend it was real though.

[electrondady1]

i watched a movie last week called avatar.

 it's a great film but it's not a documentery ,

the whole point of the photo was to illustrate the disturbed air in the wake of those turbines.

[Bruce S]

Nice photo, could be very real, the wind can do some weird things.

Here's a better shot of what they can do, http://upload.wikimedia.org/wikipedia/commons/7/73/Luftwaffe_transall_c-160d_propeller_trails_arp.jp
g..

. notice the top of the vortx?

During the days of the Star-lifter (German C-160,-?) twin turbo-props that we would jump out the back of or side depending on the "games:. You could see the moist air doing stuff that was way cool and do wish those people with the 110 cameras would post them, but anything the props were throwing around would also be thrown by the wing tips out were the Nav & Com antennas where; at least the ones we saw.

Much like the C-131s you could even jump out the shot-gun side into the prop-wake and get pushed over to the driver side of the plane before pulling the cord. Was an A-15 if you got caught after being told NOT to do, but was awesome to see.

The wake from in this pic could be very real, it passes the pixel test up to 800% , if its not then the person who did it should hang it at a museum :->.

Interesting article too, maybe a good idea to stagger the 'mills when they get that big?

Cheers;

Bruce S

[Aule Mar]

Have to remember and keep seperate a prop on an aircraft or the spoiler on a race car is driven and is moving the air, where as the turbine of a mill is being driven by the air so the preasure changes caused by each will be very different.  Its the pressure change (an increase in pressure that squeses the water out of the air and makes a the cloud).  (On a jet at altitude in the misture added by the burned fule).

[deloiter]

I have seen this same phenomenon occur with fog that is low to the ground (I'm estimating 100ft and under) as it passed by large turbines.  I topped an overpass and could see the turbines from there (not many hills here in Iowa).  Even a small amount of turbulance disturbed the smooth texture of the fog.  It was one of the coolest things I have even witnessed.  I thought that is what was shown in the picture too but the authors indicate the fog was created, not just disturbed. That I have not seen, but then there are many things in this world that I have not witnessed.  Even as a skeptic, I try to keep an open mind.  

[Ungrounded Lightning Rod]

This is something that happens in a lot of situations.  Persistent contrails are one example of a disturbance to supersaturated air resulting in condensation that persists for hours.

Back in the late '60s I took a meteorology course.  One example they talked about was an airport in Alaska that typically had a supersaturated and calm air condition in the morning.

It would be crystal clear.  Then a plane would land or take off.  And the runway would be solid pea-soup fog.  The fog would take half an hour or so to drift off the runway (but NOT dissipate) before they could launch or land another plane.  Repeat all morning...

The lecture segued into a discussion of how such a situation led to extra reflection of sunlight and lowered heating, etc. and how this showed how hard it was to get a good prediction because sometimes tiny changes were massively magnified.  (This was before chaos theory gave them a better vocabulary and more math to describe such uncertainty growth.)

[taylorp035]

fix the jp g.  to jpg