Merged DDWFTTW in a “Real” Wind

[Myriad]

I'm sure the tests provide valuable information that can be applied to the real case of the car racing on the track, but it is a simulation and I don't think anyone will claim it is exactly the same because it isn't.

You mean, no one besides the Federation Internationale de l' Automobile, the organization that sets the rules for Formula 1 racing? Those rules limit the amount of certain kinds of testing of race cars, and full-scale wind tunnel testing is restricted under the same rules as on-track aerodynamic tests, with one type allowed to be traded off for the other.

By the way, those rules were put into place because full scale wind tunnel + treadmill testing is much more effective for getting useful and accurate race performance data than track testing. But it's also more expensive, so it was seen as an unfair advantage for teams that could afford to build or hire the necessary facilities.

Respectfully,
Myriad

 

[humber]

Attach a weight to the NB balloon so it is no longer neutrally buoyant. Let it fall. Analyze how much energy is released. Hey!!! That energy is from the weight only! Where did all of humber's PE go?

Medieval imagery replaces Newton and Archimedes.

 

[humber]

eams that could afford to build or hire the necessary facilities.

Respectfully,
Myriad

And the board says you are wrong.

I would like to hear you say that is the same as the board traveling at 100mph.

 

[windgrins]

Humber: "I got Nothing!"

Assume that. Still go it all.

If you would like to have the balloon's volume change to match the very slight change in air pressure over say 100 meters, then go right ahead. As long as it stays NB as stated in the problem. See if you can find an issue.

So far you are batting "zero" with your tortured comment and everybody sees it.

You are still faking it badly.

Regards,

WindGrins

 

[windgrins]

Humber: "I got nothing!"

Medieval imagery replaces Newton and Archimedes.

Humber: In other words "I got nothing!"

 

[69dodge]

Well, let's say for example that in the ground frame the simple sail cart is moving at 3 m/s in the 5 m/s wind, in the same direction as the wind. So in a frame where the air is at rest, the sail cart is moving at 2 m/s in the same direction as the ground. What I want profpangloss to tell me is where he thinks the kinetic energy of the sail cart is coming from in this frame.

I see.

The ground does work on the cart at a certain rate. The cart does work on the air at an equal rate. So the cart's kinetic energy remains constant.

(That's in an inertial reference frame in which the air is initially at rest. The speed of the air changes slightly over time, because of the sail moving through it.)

 

[humber]

If you would like to have the balloon's volume change to match the very slight change in air pressure over say 100 meters, then go right ahead. As long as it stays NB as stated in the problem. See if you can find an issue.

So far you are batting "zero" with your tortured comment and everybody sees it.

You are still faking it badly.

Regards,

WindGrins

How about one filled at one meter above the floor, and another at 2m?
You have no idea why an NB balloon is NB.
And the next time you post electronics tests, make sure you find someone to help you.

Funny, oh so funny. The mass of the balloon has no mass, 'coz it's NB. Gravity "can't tell"
The Hindenburg did not crash to the ground until all of the "ballooniness" had escaped, at which point it gained PE and fell.

"Ballooniness" is the property of negative PE, unique to red balloons.

 

[windgrins]

Thanks JTBH!

Swing and miss.

Underlying assumption 4. "for the purpose of the discussion, we will assume that the density of air doesn't change with height over the short heights assumed for the problem nor does the balloon expand or contract-thus being always NB in the scope of the problem"

In other words - You got nothin'.

Saved me the trouble!

 

[CORed]

Wheels are often useful in this regard. A fully laden trolley is hard to get going, but once it's moving it's almost as easy to keep going as an empty one. That's inertia, being significant, out of the lab.

My first reaction on reading his statement that inertia is only significant if friction is zero was to ask why cars need brakes. For some mysterious reason, if you're going down the road at 60 mph, putting the car in neutral often doesn't seem to stop it quickly enough. I wonder why that might be.

The misinterpretation here has already been dealt with but the fundamental problem is a failure to accomodate different frames of reference. Kinetic energy is frame dependent. Who provides energy to whom is frame dependent. Rejection of the equivalence of inertial frames of reference will make this simple stuff almost impossible to understand. Trying to run before you can walk is a recipe for falling flat on your face.



It seems likely to me that what you asked them was not exactly what you imagine you asked them, or you misunderstood their answers. That is enormously more likely than the possibility of your knowing a large number of qualified physicists who do not accept the equivalence of inertial frames of reference.

 

[3point14]

Medieval imagery replaces Newton and Archimedes.

Chaucerian meter superseded by iambic pentameter.



(well, mine made as much sense as his did!)

 

[Subduction Zone]

humber, your approach would fail experimentation. What PE do you predict for a neutral density balloon one meter off of the ground? To make it easy make it a large balloon with a volume of one cubic meter.

 

[CORed]

Oh, but it does. The walker has to provide the power to walk. The belt can't do that. Why should a wheeled object be any different?
Galilean Transforms demand mechanical equivalence, and that has not been met. This is largely a waste of time, because the TM has been dismissed by Spork's selected expert, and because of carts that work without a prop.

Carts that work without a prop is still an unsubstantiated claim, but I'm sure humber still thinks he'll get one working any day now. Just a few more tweaks.

 

[windgrins]

Humber: "I got Nothing!"

How about one on filled one meter above the floor and another at 2m?
You have no idea why an NB balloon is NB.
And the next time you post electronics tests, make sure you find someone to help you.
Funny, oh so funny. The mass of the balloon has no mass, 'coz it's NB. Gravity "can't tell"
The Hindenburg did not crash to the ground, until all of the "ballooniness" had escaped.

I think I do:

1. the NB Balloon by definition weighs the amount of the air it displaces so has no forces acting on it other than gusts-This of course why we call is Neutrally Buoyant.

Do you see anything about mass in the above statement, from the problem as stated?

Feel free to try to convince the field that's not a good definition!

I think also "You got Nothing!"

As I recall on the circuit analysis:

As Pi stated. NOOOO- I want to see the mathy bits!! + and = signs, that sort of thing.

As I remember on that: "You got Nothing!"

Regards,

WindGrins

 

[humber]

I think I do:

1. the NB Balloon by definition weighs the amount of the air it displaces so has no forces acting on it other than gusts-This of course why we call is Neutrally Buoyant.

"Neutral buoyancy is a condition in which a physical body's mass equals the mass it displaces in a surrounding medium. This offsets the force of gravity that would otherwise cause the object to sink. An object that has neutral buoyancy will neither sink nor rise."

 

[quarky]

I have no business being here, as some may have noticed.
My background is chemistry, not mechanical engineering.
Yet, I have drifted, due to boredom, or interest in mechanical engineering stuff.
I dig building stuff. I gave up on building molecules about the time when some of the molecules became really interesting, and illegal.

hence, i seek a synopsis of the overall argument here:

Forgive me for not following every post in this debate.

To reduce it to humber vs spork:

Is the main bitch about the definition of "directly" in the ddwfttw?
Or is it more than that?

As in, spork and JB bribed judges?
The videos were fake?
Does humber allow that the cart did achieve speeds faster than the wind?
But they cheated, because the wind changed direction? hence, not 'directly'?

Or is it more than that?

Color me confused about this.

Did spork and "company" simply lie, and create bogus footage?
Or is humber's objection mostly about the variation of the wind in the test runs?

As far as I can tell, the only reason that this thread goes on and on is because of humber's objections.
And now, there are implications that the new kid in town is a sock-puppet of ancient objection humanoids.

I have brought up several obscure metaphors to explain some of the subtle (non-intuitive) aspects of this understanding.

I remain confused. Not about the results. Not about the energy to be tapped between these frames of reference.

My confusion lies elsewhere.

But as mentioned, I'm no mechanical engineer.
Even if I have built some seriously strange mechanical devices myself, even when I should have been cleaning the kitchen.

Please help me, friends.

 

[69dodge]

Next the observer moves at 5 m/s along with the wind so the air is now stationary relative to the observer. The ground is moving relative to the observer at -5 m/s and the cart at -2 m/s all relative to our observer. But all that is relative to the observer and does not represent any change in the physical situation that existed in the original reference frame! The source of energy for the cart is still the same as it always was, the wind!

In that frame, the air isn't moving. So, in that frame, it has no energy. How can it give any energy to the cart, then?

What you are in effect saying is that the choice of observer changes the reality of what is being observed.

No. He's saying that "the reality of what is being observed" does not include which way the energy is flowing. That depends on the choice of observer.

Do you really think that if you hop on a motor scooter and travel at the speed of the wind, that somehow changes the source of energy for the sail cart from wind to ground?

Yes.

Choice of reference frame can change the measured kinetic energy of things in those frames, but it won’t change the source of energy[...]

The "source" of energy just depends on which object's kinetic energy is increasing and which object's is decreasing. If the objects' kinetic energies are different in different frames, why can't the changes in those energies also be different in different frames?

[...]and that can be confirmed with such things as thermal imaging, for example. In a thermal image, the treadmill motor will always be identified as the energy source, no matter how fast the observer is moving.

Generators get hot too, not just motors, but the energy goes the opposite way. So I don't see how thermal imaging helps you identify the energy source.

You could attach a generator to a treadmill. Then, a person walking on the treadmill would be the source of the energy, but the generator would still get hot.

 

[quarky]

I have no business being here, as some may have noticed.
My background is chemistry, not mechanical engineering.
Yet, I have drifted, due to boredom, or interest in mechanical engineering stuff.
I dig building stuff. I gave up on building molecules about the time when some of the molecules became really interesting, and illegal.

hence, i seek a synopsis of the overall argument here:

Forgive me for not following every post in this debate.

To reduce it to humber vs spork:

Is the main bitch about the definition of "directly" in the ddwfttw?
Or is it more than that?

As in, spork and JB bribed judges?
The videos were fake?
Does humber allow that the cart did achieve speeds faster than the wind?
But they cheated, because the wind changed direction? hence, not 'directly'?

Or is it more than that?

Color me confused about this.

Did spork and "company" simply lie, and create bogus footage?
Or is humber's objection mostly about the variation of the wind in the test runs?

As far as I can tell, the only reason that this thread goes on and on is because of humber's objections.
And now, there are implications that the new kid in town is a sock-puppet of ancient objection humanoids.

I have brought up several obscure metaphors to explain some of the subtle (non-intuitive) aspects of this understanding.

I remain confused. Not about the results. Not about the energy to be tapped between these frames of reference.

My confusion lies elsewhere.

But as mentioned, I'm no mechanical engineer.
Even if I have built some seriously strange mechanical devices myself, even when I should have been cleaning the kitchen.

Please help me, friends.

 

[humber]

I think I do:
Feel free to try to convince the field that's not a good definition!
1. the NB Balloon by definition weighs the amount of the air it displaces so has no forces acting on it other than gusts-This of course why we call is Neutrally Buoyant.

Weight = m*g

"Neutral buoyancy is a condition in which a physical body's mass equals the mass it displaces in a surrounding medium. This offsets the force of gravity that would otherwise cause the object to sink. An object that has neutral buoyancy will neither sink nor rise."

As I recall on the circuit analysis:
As Pi stated. NOOOO- I want to see the mathy bits!! + and = signs, that sort of thing.

Sure you do...sure you need to, in case I take yours apart.

 

[Dr. Keith]

hence, i seek a synopsis of the overall argument here:

Forgive me for not following every post in this debate.

To reduce it to humber vs spork:

Is the main bitch about the definition of "directly" in the ddwfttw?
Or is it more than that?

My understanding is that it is more basic. Along the lines of Spork proposed a device to do something odd. Due to resistance Spork built a prototype of the device and ran some tests on a TM. Eventually Spork even built a full scale cart and ran tests in the wild, some even being measured by third parties.

Somewhere along this humber said nope can't be done. So far as I can tell humber hasn't elaborated much beyond you can't go faster than wind directly downwind and any claims that you have is just a lie and part of your cult.

As in, spork and JB bribed judges?
The videos were fake?
Does humber allow that the cart did achieve speeds faster than the wind?
But they cheated, because the wind changed direction? hence, not 'directly'?

This is the part I don't get, either. Humber claims that the cart was not directly down wind, but has never been clear about how the cart as built could benefit from being slightly off DDW. He claims that it is just tacking, but I don't see any structure that could take advantage of said tacking and he has never explained how the BB could tack more efficiently than any other sail cart traveling so close to DDW.

As far as I can tell, the only reason that this thread goes on and on is because of humber's objections.

Yep. And the main characteristic of those objections is their lack of cohesion.

My confusion lies elsewhere.

But as mentioned, I'm no mechanical engineer.

I think a degree from the psych department would be more useful. This is delving into the realm of pathology.

 

[humber]

Is the main bitch about the definition of "directly" in the ddwfttw?

Mostly. But the TM has nothing to do with a cart in the wind. It is visual illusion, made real. Laughable. It is fully explicable by conventional mechanical analysis. It has nothing to do with Galilean Transforms, but the result of trial and error.

As in, spork and JB bribed judges?

No, Spork previously tested the cart in similar gusty and changing wind conditions, and with full knowledge that the run was too short to show steady-state so allowing transient winds to produce the desired result.
That had already been done by Bauer in the '60's.

NALSA were led to believe that the trail was about top speed and not sustained >WS performance, so ignored how the cart got to above WS to the point in which it was allowed to be pushed above WS.

The videos were fake?

The videos are selected to show only the apparent successes, and not the failures. In the Jenkins' video, the cart spends 1min 30 below WS when the cart was ddw. That constant <WS speed was predicted by Harold Bricer's calculation, and is valid proof that he was right. However, the trial continued until the wind changed and the cart tacked. The vane shifts at least 50 degrees, and even shows a headwind.

The wind in the record trial changes by up to 40 degrees. That is seen only in the raw data, and not in the published chart. The only NALSA member was Bob Dill, while there were perhaps 10-20 cart supporters present, so any objections would have been railroaded, had he made them.

Does humber allow that the cart did achieve speeds faster than the wind?
But they cheated, because the wind changed direction? hence, not 'directly'?

Fixed the race, biased the rules, and knowingly cheated by not going ddw.

Did spork and "company" simply lie, and create bogus footage?
Or is humber's objection mostly about the variation of the wind in the test runs?

It's about claiming one thing, and testing another. That is not only cheating, but underhanded fraud.

As far as I can tell, the only reason that this thread goes on and on is because of humber's objections.
And now, there are implications that the new kid in town is a sock-puppet of ancient objection humanoids.

The record supports a lie. That has wasted the time of SJSU, NALSA and others. The plan is to use that same sham, to launch a bogus power generation scheme.