Split Thread The validity of classical physics (split from: DWFTTW)

[Brian-M]

The whole thing is like a Monty Python skit that has gone on way too long.

I think it's the "I'd like to have an argument" skit... although at times I feel like I've walked into the "Being hit on the head lessons" room by mistake.


ETA:
I think I've just made far too many posts in one go. I hope nobody begins to mistake me for Humber.

 

[CORed]

Shhhh.... If you tell him that the speed of the boundary layer is infinetly graduated between surface-speed and wind-speed it might make his head explode.

But then again, that might not be a bad thing.

I think it's entirely possible that his head, or at least part of it, already has exploded.

 

[Dan O.]

ETA:
I think I've just made far too many posts in one go. I hope nobody begins to mistake me for Humber.

If you hadn't said anything, I would have assumed that humber was posting between your posts.

BTW, has humber answered my questions about equivalency? That would almost be worth taking him off ignore to see.

 

[Christian Klippel]

...might make his head explode.

But then again, that might not be a bad thing.

Hmmm, i always thought that it is called implosion, when a vacuum is involved....

Greetings,

Chris

 

[Dan O.]

Hmmm, i always thought that it is called implosion, when a vacuum is involved....

You have to expect an occasional vector will be reversed with this one.

 

[spork]

I think I've just made far too many posts in one go. I hope nobody begins to mistake me for Humber.

Nope. You're still using complete sentences.

 

[humber]

It appears that humber has indeed ignored my quiz about the Japanese baseball gun, so spork is right again. Not surprising.

Well jjcote, if it is as easy as this little canard, it won't be a problem.

Okay, we have a smoke generator sitting on the ground. There is a 10 m/s wind blowing out of the south, and we are approaching the smoke generator at 10 m/s, northbound (i.e. at windspeed) in some sort of conveyance (not necessarily wind powered). When we are 10 m from the generator, it emits two puffs of smoke, one at eye level, the other at ankle level. What do we see? The puff that is at eye level travels northward at 10 m/s, and remains 10 m in front of us, while the one at ankle level, in the boundary layer, moves forward at only 6 m/s, so we close the distance to it at 4 m/s, and we pass by it in 2.5 seconds.

Yes, yes, get on with it...

Now we have a smoke generator attached to a (sufficiently large) treadmill belt that is moving from north to south at 10 m/s. It is in a room with still air, and we are maintaining our position with respect to that air (and to the "floor") by moving relative to the belt at 10 m/s in some sort of conveyance, so the smoke generator is coming toward us at 10 m/s. When the smoke generator is 10 m in front of us, it emits two puffs of smoke, one at eye level, the other at ankle level. What do we see? The puff that is at eye level stays put relative to the air (and to the "floor"), and remains 10 m in front of us., while the one at ankle level, in the boundary layer, is dragged back by the belt at 4 m/s, and we pass by it (or it passes by us) in 2.5 seconds. Exactly the same.

Oooh, no, JJcote, you are using the apparent closing distance, but ignoring the direction. In real wind, the difference between the flows is constant regardless of traveler velocity.
Try this using the same situations that you have described.
Stand in real wind while holding a paddle device, so that the axle is above the boundary layer, with the top and bottom blades driven by the wind and boundary respectively. This should yield a difference of '4m/s' (CW) and then again at windspeed. (10 - 6 = 4).

The belt is not the same. At windspeed, (taken from he cart) the paddle will turn ( 0 - 6) -6m/s (CW). Going with the belt will be ( 10 - 6) 6m/s (CCW) ETA:4m/s (CCW)This is tricky. If you stand on the belt, the air right next to the belt will be at 0 w.r.t you, so the slower flow of 6ms, can be said to move away from you at 4m/s. The air over the top (from your back) is coming to the paddle at 10m/s, so the difference is 6m/s (CCW.) ETA: 4m/s (CCW)
ETA:
If the lower paddle touches the belt, the paddle will stop, and so for a flow going at the speed of the belt. A flow of 6m/s will therefore be 4m/s slower, turning the paddle 4m/s (CCW)


You have to agrees that at some point when moving up the belt, the flows will be equal and opposite, so the paddle will stop. This will not happen in the wind.

 

[John Freestone]

I think Humber's last rant was finally too much for me. I've got to pull myself away from this train wreck before my sanity is seriously endangered. I'm starting to hear futile cries of "The treadmill is not a road!" in my sleep. The whole thing is like a Monty Python skit that has gone on way too long.

I will just note one possible motive for Humber's bizarre notions that I don't think has been mentioned. There is a category in the JREF's Pigasus Awards http://www.randi.org/site/index.php/pigasus-awards.html, added in 2005, which does not appear to have been awarded yet. It is for "Most Persistent Refusal To Face Reality". By god, if Humber hasn't earned this in runaway fashion, there is no justice in the world. I applaud him for an effort that has really set new pinnacles of clue-resistance, and would like to be the first to nominate him to be the inaugural recipient of this esteemed honor.

Tunny
In the Humberverse, of course, this award will go, for the umpteenth year in a row, to "Everyone Else in the World But Humber", for their persistent and unanimous refusal to accede to his view of, well, anything.

Oh I enjoyed reading that, Tunny, especially "pinacles of clue-resistance". I second it, or, if it's already been seconded, I third...let's just say I n+1th it, where n is how much it's been nthed.

 

[humber]

Oh I enjoyed reading that, Tunny, especially "pinacles of clue-resistance". I second it, or, if it's already been seconded, I third...let's just say I n+1th it, where n is how much it's been nthed.

What about an award for the "Most persistent denial that the boundary layer is going the wrong way"?

Did you see my reply to jjcote, John?

 

[John Freestone]

Tunny, you can be the seconder for my earlier post... although I sure others will have prior claims on being the first to note humber's almost unbelievable persistence. Come to think of it, Monty Python has probably now been mentioned in this thread more often than agreement with humber on any non-trivial matter has ever been noted (and perhaps even when including the trivial cases)!

The only thing is that while awarding people stoopid-prizes is fun, I don't think we should encourage that behaviour too much. Your post had too much of the 'round of applause' and 'top marks for persistence' etc. for my liking. OTOH, I realise that was less than 300 posts in, and there was still some hope that he was 'genuinely interested in reaching some kind of common agreement'. The meaning of any award given to someone so skilled in ambiguity needs to be utterly unambiguous (what am I saying?: as spork observes, he'll probably still celebrate that it means he's right).

My recent fave is "Smoke from the future, would pass by you, at full essentially windspeed, in the opposite direction no matter what." I can't get Deep Purple out my head now.

 

[humber]

The only thing is that while awarding people stoopid-prizes is fun, I don't think we should encourage that behaviour too much. Your post had too much of the 'round of applause' and 'top marks for persistence' etc. for my liking. OTOH, I realise that was less than 300 posts in, and there was still some hope that he was 'genuinely interested in reaching some kind of common agreement'. The meaning of any award given to someone so skilled in ambiguity needs to be utterly unambiguous (what am I saying?: as spork observes, he'll probably still celebrate that it means he's right).

My recent fave is "Smoke from the future, would pass by you, at full essentially windspeed, in the opposite direction no matter what." I can't get Deep Purple out my head now.

Persistence is fertile.

Still not going with the flow? An upstream object seen by one observer, is not the future for someone downstream?

 

[John Freestone]

What about an award for the "Most persistent denial that the boundary layer is going the wrong way"?

Ah yes, about 400 years of denial by everybody.

Did you see my reply to jjcote, John?

With or without a paddle, you're still up the same creek.

 

[John Freestone]

Persistence is fertile.

Spread it on your roses.

Still not going with the flow? An upstream object seen by one observer, is not the future for someone downstream?

Well since you ask, you appear to have said the same thing twice in a convoluted way. An upstream object is 'the future' for someone downstream because they are downstream. That's why the object is upstream of them. But I was just laughing because 'future smoke' was an odd idea. I can see what it means in your scenario, and it's just a shorthand I suppose. You mean the flow or the smoke that will reach the observer at some later time. Fine.

If you read carefully and understood jjcote's explanation, or Brian-M's, or anyone's, you would see that they are right. The flow grades from 0 w.r.t. the surface to whatever maximum it gets to. That is a simple fact in both situations. Its direction and change of direction speed with height are also the same. So if you're standing on one surface with wind behind you, or standing on one surface moving backwards, you experience the same windspeeds in the same direction at all heights.

I don't believe I'm still explaining it!

 

[humber]

What? I should take the belt off my treadmill and then my wind tunnel might disappear? So the wind tunnel can only be relevant because of a belt (on a treadmill) inside it? Have I got that right?

No, Clive, it was never there. The belt turns the wheels. Remove that, and what happens other than cessation of the cart's mechanical processes?

Anyway, please, just carefully read Brian-M's post again Humber, instead of just closing your eyes (and mind) and continually shooting from the hip.

Ditto. Brian-M, and others, have posed that same or similar test many times. Of course I do not agree with their conclusion, because that very conclusion, is the result I already deny. I don't need a 'walkthrough'. I 'get' it, but I say it is wrong. There are facts are not concordant with the conclusion.

I think you will find that his wind tunnel on the truck has no treadmill or other moving belt in it. You appear to have misinterpreted his description by assuming he meant there was a treadmill inside the wind tunnel and so on.

It does not matter. It fails before that point, so any subsequent conclusions and later developments to include a belt, are false. When I interwove 'a belt is not a road' and 'to its forgone conclusion', I am saying that I am already aware of every step, and where it will lead. To offer this repeatedly, means that my objections give way to the assumption that I don't understand the argument, rather than refute it.

Start again. Just allow for a solid flat floor on the bottom section of the tunnel. The cart can then be tested by placing it, heading downwind, on the floor of the wind tunnel at whatever speed we want to look at. After that it can move freely just like the same cart on the "real ground" in the "real wind". In other words, the wind tunnel is only there to produce a nice steady wind (and we're starting with that wind tunnel perched on top of a truck that is parked - thus not moving relative to the ground).

Who doubts that a wind tunnel with wind, is not valid? That is not the treadmill model, nor can any equivalent without wind be derived. There must be moving air.
The belt is also the wind's power. It drives the wheels not the propeller. This is not "equivalent" to a cart, on a road in wind. When moving with the belt, it is closer, to a model because there is moving air, but it still not correct.

Can you do the same for a speedboat? Perhaps there is an equivalent, but I doubt that would be the case if the propeller were in the air, and not in the water. Just because it may be possible to 'construct' models with equivalent velocities, does not mean that every permutation is correct.

 

[humber]

Spread it on your roses.

Well since you ask, you appear to have said the same thing twice in a convoluted way. An upstream object is 'the future' for someone downstream because they are downstream. That's why the object is upstream of them. But I was just laughing because 'future smoke' was an odd idea. I can see what it means in your scenario, and it's just a shorthand I suppose. You mean the flow or the smoke that will reach the observer at some later time. Fine.

If you read carefully and understood jjcote's explanation, or Brian-M's, or anyone's, you would see that they are right. The flow grades from 0 w.r.t. the surface to whatever maximum it gets to. That is a simple fact in both situations. Its direction and change of direction speed with height are also the same. So if you're standing on one surface with wind behind you, or standing on one surface moving backwards, you experience the same windspeeds in the same direction at all heights.

I don't believe I'm still explaining it!

Yes, to the first remark, John, but the jjcote's solution is not correct. I have refuted it in a recent post. There is definitely a difference. I say the smoke shows that , but now the paddle wheel too.
What more is there to say? I did correct it, but that did not change the original conclusion.

 

[Clive]

Brian-M, and others, have posed that same or similar test many times. Of course I do not agree with their conclusion, because that very conclusion, is the result I already deny. I don't need a 'walkthrough'. I 'get' it, but I say it is wrong. There are facts are not concordant with the conclusion.

See the quote below for what Brian-M asked you to do. It's pretty simple. It's not primarily a 'walkthrough' to help you 'get' it. It's a series of steps where only one thing changes each time. Isolating the changes in that way might help us understand your point of view better than we do now, but only if you do your part also.

What I want you to do is point out exactly where you disagree with my expected outcome, and tell me what you think would happen in that instance, and why.

Brian went to a lot of trouble to clearly describe the various stages. If you expect any respect from me at all (and I suggest others reading these posts would feel similarly) then I suggest the very least you need to do now is respond to Brian's post as he asked you to do. You definitely haven't done that yet, and it shouldn't take much effort on your part if you have any integrity at all.

ETA: I should note that you did respond to Brain's post earlier but that was also when you apparently did not understand it properly. Assuming a belt or treadmill was part of every stage meant you basically just regurgitated your "a belt is not a road" statement over and over again, but that assumption was incorrect. I don't think it's difficult to see what most people will infer if you suddenly baulk now, given that your earlier misunderstanding has been pointed out.

 

[humber]

See the quote below for what Brian-M asked you to do. It's pretty simple. It's not primarily a 'walkthrough' to help you 'get' it. It's a series of steps where only one thing changes each time. Isolating the changes in that way might help us understand your point of view better than we do now, but only if you do your part also.

How can that help? I already fully understand it! It is simply presumed that it is me that is making the mistake. There is no point in going through the motions just for the sake of them.

Brian went to a lot of trouble to clearly describe the various stages. If you expect any respect from me at all (and I suggest others reading these posts would feel similarly) then I suggest the very least you need to do now is respond to Brian's post as he asked you to do. You definitely haven't done i that yet, and it shouldn't take much effort on your part if you have any integrity at all.

It will only serve to pointlessly repeat the process.
I have told him, and anybody else that has taken the trouble, that I appreciate that. That does not make it correct, or that I should jump through every hoop. I make effort too.
I have been trying to breakdown the model, to show that it has errors. By normal practices, it is not acceptable to ignore them on the assumption that they don't matter, or that the initial supporting premise is correct.
The boundary flow is wrong. But there is a blunt and flat refusal to actually think the responses through. They are wrong.

 

[Christian Klippel]

But there is a blunt and flat refusal to actually think the responses through. They are wrong.

Yes, there is. But only on your side of the screen, not on ours. It is your sheer ignorance that is the cause. You are wrong, not us.

Again you proved that no matter what, you will refuse to learn. The big failure is on you, not on us. You assume you are right and based on that refuse any explanation without even thinking about it. You think you have superior knowledge, while in fact you know nothing at all.

 

[Clive]

The boundary flow is wrong.

So you keep saying. Others (including myself) keep saying that it is you that is wrong. (You've still got it wrong with the paddle wheel also.) But you have also said several times you don't have a problem with a wind tunnel that has air moving through it ("real wind"), and that is Brian-M's starting point in his post with the various stages.

So, which (if any) do you think is the first of Brian-M's stages where the boundary layer is wrong?

 

[humber]

See the quote below for what Brian-M asked you to do. It's pretty simple. It's not primarily a 'walkthrough' to help you 'get' it. It's a series of steps where only one thing changes each time. Isolating the changes in that way might help us understand your point of view better than we do now, but only if you do your part also.

How can that help? I already fully understand it! It is simply presumed that it is me that is making the mistake. There is no point in going through the motions just for the sake of them.

Brian went to a lot of trouble to clearly describe the various stages. If you expect any respect from me at all (and I suggest others reading these posts would feel similarly) then I suggest the very least you need to do now is respond to Brian's post as he asked you to do. You definitely haven't done i that yet, and it shouldn't take much effort on your part if you have any integrity at all.

It will only serve to pointlessly repeat the process.
I have told Brian-M, and anybody else that has taken the trouble, that I appreciate that. That does not make it correct, nor that I should jump through every hoop. I make effort too.
I have been trying to breakdown the model, to show that it has errors. By normal practice, it is not acceptable to ignore them on the assumption that they don't matter, or to maintain the initial supporting premise in spite of those errors.
The boundary flow is wrong. But there is a blunt and flat refusal to actually think the responses through. They are wrong.

The idea that a car moving along a road can be emulated by holding the car still, and moving the road backwards is false. Dynamometers aside, the most the road can ever do is emulate the road surface. A detail if you are interested in the boundary layer or wheel behavior. That is not an assumption, it is a fact. Linear motion cannot be emulated by a model stationary on a belt. A model that uses the contrary as a premise, is not even a candidate.
The observer on the belt is not correctly modeled. The model is generated as follows:
The cart is said to be at windspeed, and is seen from that perspective. The road is then said to move right to left upon that basis. However, when going from the model to reality, the road is fixed, and the cart in motion. That is not the meaning of equivalence.