Conversation continued from YouTube:
James McGinn:
Hi Rick. I"m an atmospheric scientist. My specialty is the the aerodynamics that occur naturally in the atmosphere associated with storms, especially severe weather. I think I can improve your explanation of how/why the upper limit of velocity on your DDWFTTW isn't the velocity of wind but, actually, the velocity of air pressure (which is the same as that of the speed of sound).
Intuitively we assume that the force that is pushing the vehicle is the wind. Actually it isn't. The force that is pushing the vehicle is air pressure. And the speed limit of air pressure is the speed of sound.
Would you be interested in a really tough question--a question that was designed to put you on the spot? If not I won't bother. But if you can commit to making an honest attempt at answering it, I will take some time to put together a scenario and some questions that, I assure you, will get to the crux of how/why this vehicle is able to move downwind faster than the speed of the wind. Are you interested??
Rick Cavallaro:
I think I understand it. I will take a shot at answering your questions.
Here is my challenge:
Let's consider your DDWFTTW going downwind. Let's assume it starts with a 14 mph wind. Within two minutes it is up to 14 mph. Two minutes later it gets to 32 mph (over 2X). It stays at that speed for 2 minutes, and then let's say the wind completely dies, dropping to zero. The DDWFTTW gradually slows down and after 2 minutes it stops.
Now lets consider three 10 second snippets in this time series:
1) While it is accelerating, below wind speed:From 1:00 to 1:10. (Wind speed 14 mph)
2) Still accelerating, above wind speed: From 3:00 to 3:10. (Wind speed 14 mph)
3) Maintaining top speed: From 5:00 to 5:10. (Wind speed 14 mph)
4) decelerating, losing speed: From 7:00 to 7:10. (Wind speed 0 mph)
At #2 the DDWFTTW is accelerating. What is the source of the energy that is causing/producing this acceleration?
a) The wind?
b) Air pressure?
c) Something else?
With respect to the source of the energy involved, how would you differentiate between the acceleration at #1 and the acceleration at #2?
Rick Cavallaro
The source of energy is always the relative motion between the air and the ground. It slows the air relative to the ground as it passes through it. I wouldn't differentiate the source of energy in those two cases because the source of energy is in fact the same.
James McGinn
I agree that it slows the air relative to the ground as it passes. However, I do differentiate. If wind was the only source of energy the vehicle could never get going faster than the speed of the wind. Aerodynamics underlie an exchange by which air pressure is the source of the energy that allows the higher speeds of the vehicle.
In explaining how any sail powered vehicle can achieve a velocity that is greater than the velocity of the wind one has to invoke aerodynamics and the fact that the speed limit of the source of the energy that is associated with aerodynamics is not the wind but air pressure. And the speed limit of air a pressure is very high, literally the speed of sound.
The speed limit of the wind in this scenario is 14 mph. It cannot push something to go faster. However, it can be the source of the energy that achieves the laminar flow of the aerodynamics that, literally, tap into the abundant energy in air pressure.
The energy that keeps an airplane from falling out of the sky does not come from the thrust of the airplane's engines, it comes from air pressure. The thrust of the airplane's engines provides the energy that allows the airplane overcome drag and achieve a velocity that enables laminar flow over the top of the plane's air-foil wings. Accordingly, the energy from the thrust of the airplane's engines is conserved in the velocity of the airplane. It being a consequence of velocity, laminar flow removes the energy of air pressure from the top of the wing. It does not remove it from the bottom of the wing. Consequently, energy literally flows up into the wing, producing an acceleration force, lift. And so, aerodynamics involves the rules/principles by which the abundant energy in air (air pressure) can be tapped into or channeled.
All in all, aerodynamics involves an exchange, with air pressure being the source of the energy flow that causes lift (an acceleration force). The same is true for DDWFTTW and any sail powered vehicle.
And so, if we were to model the pathway of the energy that causes the lift on an aircraft it originates in the atmosphere. It does not originate with the airplane's engine. It is extracted from the atmosphere by the air foil. (Nevertheless, the atmosphere does not experience a net loss in energy as a result of the aircraft passing through it but actually experiences a net gain in that the amount of energy associated with thrust/drag more than compensates for the loss of energy associated with lift.)
In a wind powered vehicle the wind is analogous to the motor of the aircraft. Wind removes the air pressure from the back of the sail or air foil. Air pressure is what pushes the vehicle. Energy is conserved in the speed of the vehicle and by tacking to maintain laminar flow or, as in the DDWFTTW, the energy is also conserved in the momentum of the spinning propeller/turbine.
In a sail powered vehicle tacking explains how laminar flow is maintained at higher speeds. With DDWFTTW the spinning motion of the propeller/turbine explains how laminar flow is maintained at higher speeds. However, explaining how either achieves a speed faster than the wind requires a source of energy that is going faster than the wind, air pressure, which has a speed limit that is the same as the speed of sound. People are generally unaware that air molecules in still air actually are moving over 700 mph and have a lot of energy.
Lack of awareness of the abundant energy in the atmosphere that is associated with air pressure is one of several conceptual misconceptions that has brought progress in severe weather research to a standstill:
http://www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=10&t=16329 Rick:
You have a number of misconceptions here.
Jim:
Not likely. I'm an expert on this subject. Feel free to delineate these alleged misconceptions. I know you won't be able to.
Rick:
But your basic assumption would suggest that this should be limited to the speed of sound since air pressure moves at the speed of sound.
Jim:
Something can't push something faster than it is going itself without some kind of mechanism, which you have not described here.
Rick:
But that is not the case with this. This can in principle operate faster than the speed of sound.
Jim:
What principle? I think you are mistakenly assuming that the mechanics of DDWFTTW work like the gear ratios in a car to explain the higher speeds. That is, definitely, wrong. Its the speed of air molecules as realized through aerodynamics that explains the high speeds. Your mechanics explains how laminar flow is maintained at higher speeds without tacking. It doesn't explain the higher speeds themselves. If your mechanics did explain the higher speeds then other sail powered vehicles that lack these mechanics could not go faster than speed of wind.
James McGinn / Solving Tornadoes
Lookout For Bill
http://www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=10&t=16582#p117060?