New Mexico Fire-Devils

Bob Korves wrote:
Marc Ramsey wrote in
. net:

http://vortexengine.ca/

Wanna buy a bridge to go with that Atmospheric Vortex Engine?
-Bob

Quite. The Solar Chimney technology (trialled in Spain and, I think,
currently being worked on in Australia)

http://www.globalwarmingsolutions.co...ar_chimney.htm

looks likely to be much more efficient.


--
martin@ | Martin Gregorie
gregorie. |
org | Zappa fan & glider pilot

I can think of the following reasons why a visibly rotating dust devil =
can end in an apparently spin-less cloud:

1. The angular momentum carried in a dust devil is partially dissipated =
to the neighbouring air through the normal momentum transfer mechanisms =
that occur in all fluid flows, and very strongly in turbulent flows.

2. A rising thermal collects a large amount of surrounding air, =
especially in its final (or higher) stages. This incorporated air likely =
has statistically random angular momentum, thus diluting the specific =
angular momentum in the whole thermal.

3. The thermal widens and the rotation speed drops by the inverse square =
of the radius.

4. The angular velocity drops by the inverse cube of the radius.

So a ten metre wide dust devil rotating once every two seconds can turn =
into a two hundred wide cloud rotating once every sixty hours, without =
violating any physical laws.

Regards

Oops! Made a mistake in point 4 of previous message.

So, where I wrote "once every sixty hours", please
read "once every six hours".

The cloud will anyway seem devoid of rotation to any human observer.

Regards

The idea looks to be interesting, although the problems in producing a
chimney
with a height of 1000 metres would be interesting. :-(

And more importantly, isn't this a bit high for a first thermal off of the
launch? ;-)

Be nice to have a dedicated thermal just off the runway though!

Malcolm...

"Martin Gregorie" wrote in message
...
Bob Korves wrote:
Marc Ramsey wrote in
. net:

http://vortexengine.ca/

Wanna buy a bridge to go with that Atmospheric Vortex Engine?
-Bob

Quite. The Solar Chimney technology (trialled in Spain and, I think,
currently being worked on in Australia)

http://www.globalwarmingsolutions.co...ar_chimney.htm

looks likely to be much more efficient.


--
martin@ | Martin Gregorie
gregorie. |
org | Zappa fan & glider pilot

There are some very optimistic people working on a 1000m high chimney in the prime soaring country north of Mildura, Australia at this very moment.
I asked the question on our aussie site if it could be used as a thermal generator for gliding, everyone was confident it would be no problem BEFORE twin towers 911, not now.
Another good one George, thanks.

Francisco De Almeida wrote:
Oops! Made a mistake in point 4 of previous message.

So, where I wrote "once every sixty hours", please
read "once every six hours".

The cloud will anyway seem devoid of rotation to any human observer.

I certain I've read that, on a calm day, if you lie on your back and
cloud watch, you CAN see them rotate, just very slowly.

Can't remember where I read that, though.


--
martin@ | Martin Gregorie
gregorie. |
org | Zappa fan & glider pilot