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Merged DDWFTTW in a “Real” Wind
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CORed
Penultimate Amazing
Nice page on gas laws, but doesn't address the issue of whether you understand the distinction between velocity and speed.
It appears that you don't.
ETA: It appears that the cited page uses velocity as if synonymous with speed, which is not unusual, but not strictly correct.
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Subduction Zone
Muse
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Vectors are no friends of humber. You should have seen some of his early attempts at doing a Galilean Transformation. He finally found one physicist who did not understand what was being tested with the treadmill and he has stuck with him, even though the same physicist said that DDWFTTW does not break any physical laws.
CORed
Penultimate Amazing
I participated in that thread, and even deconstructed some of his attempts to show that the treadmill was different from the "real" wind. It got into all kinds of irrelevant esoterica about boundary effects and whatnot. Invariably, humber would take some quantity, neglect to transform it to the correct frame of reference, and say "See, it's different." He just couldn't seem to understand that you add the same value to everything. And these were all two dimensional models, where all you had to do was add and subtract. I'm sure actual vectors would make his head explode.
ETA: Humber's very good at extracting one or two sentences from a textbook or the responses from a physicist that support him (or that he thinks does) and ignoring the vast majority of it that says he's completely wrong.
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F_drag = 1/2.p.A.Cd*V^2. Over-simplified.
.
Galilean Relativity concerns only a bit of the picture, and things have moved on
since then...
Blah..blah..added mass..Reynolds..
Vs = velocity of sphere.
Va = velocity of air
ma = added mass at boundary.
3/4.pi.a^3 = Sphere volume
p = air density
Fx = -Vs ( 1/2.p.3/4.pi.a^3) Moving sphere, still air
Fx = Va ( p.3/4.pi.a^3 + ma) Moving air, still sphere
Moving sphere in moving air
Fx = -Vs (ma) + Va (p.3/4.pi.a^3) = Va (p.3/4.pi.a^3) + ma(Va - Vb)
No solution where F = 0 and/or Va = Vb.
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Utterly trivial.
No it does not, and all gas velocities are measured that way, and not just the reference I found, which was selected as being easiest for you to understand.
It's RMS. The velocity has a non-zero value.
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temporalillusion
Technical Admin
Moving air, still air, moving sphere, still sphere, with respect to what?
recursive prophet
Graduate Poster
Seems much of what Humber says could be couched in such a way Red. I suspect that quite often he is not necessarily wrong in his definitional stretches.
How so? At what point does the Demon intercede as Maxwell's does?
Not really settled Mod. It was renewed at RDF and has come up countless times at TR.
WRT Humber-physics, they certainly draw in the punters, eh? The original thread here started by my_wan was split off to one called The validity of classical physics, if you recall. It went on to break daily activity records for the science forum while its predecessor about the cart quickly faded into the archives. I can present very clear numbers from 3 different sites that show to what an amazing extent traffic on various ddw.. threads ebbs and flows around Humber’s posts. On these 3 alone he has engendered about two thousand pages of replies. My point is that one has to wonder why so many ostensibly bright people like yourself would bother to engage him if in fact there was nothing but nonsense behind all of his claims?
Modified
Philosopher
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My point is that one has to wonder why so many ostensibly bright people like yourself would bother to engage him if in fact there was nothing but nonsense behind all of his claims?
It is a challenge to try to get someone who is so irrational to realize that he is, or admit that he is, or to let him box himself into a corner by using his own arguments to make him look more and more silly. It seems clear by now that only the last of those is possible, but it's still mildly entertaining.
And of course there is still occasional useful physics insight for newcomers.
I didn't think it was possible, but this is even dumber than when you tried to subtract the Stokes formula from the Rayleigh formula.
CORed
Penultimate Amazing
Yes it was, and yet you screwed it up.
When the air is not moving then you don't use the formula for when the air is moving.
The sphere. Motion is relative. Are you now claiming that when the balloon and fluid are not at the same speed, that the relative motion is not zero?
No need to mention the ground or the planets.
You have been sold a half-baked idea that relative something to do with absolute motion and you need to specify that. It doesn't, and the argument is internally inconsistent. Now where did you get that from? Was it from a visitor from Planet Oil Barrel, perchance?
A Stirling engine is a heat engine operating by cyclic compression and expansion of air or other gas, the working fluid, at different temperature levels such that there is a net conversion of heat energy to mechanical work.[1][2]
Like the steam engine, the Stirling engine is traditionally classified as an external combustion engine, as all heat transfers to and from the working fluid take place through the engine wall. This contrasts with an internal combustion engine where heat input is by combustion of a fuel within the body of the working fluid. Unlike a steam engine's (or more generally a Rankine cycle engine's) usage of a working fluid in both its liquid and gaseous phases, the Stirling engine encloses a fixed quantity of permanently gaseous fluid such as air.
Laughs.
http://physicsworld.com/cws/article/news/26939
Not really settled Mod. It was renewed at RDF and has come up countless times at TR.
WRT Humber-physics, they certainly draw in the punters, eh? The original thread here started by my_wan was split off to one called The validity of classical physics, if you recall. It went on to break daily activity records for the science forum while its predecessor about the cart quickly faded into the archives. I can present very clear numbers from 3 different sites that show to what an amazing extent traffic on various ddw.. threads ebbs and flows around Humber’s posts. On these 3 alone he has engendered about two thousand pages of replies. My point is that one has to wonder why so many ostensibly bright people like yourself would bother to engage him if in fact there was nothing but nonsense behind all of his claims?
Because I am right.
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CORed
Penultimate Amazing
The claim was that some microbes are asymmetrical with respect to Brownian motion and use this to move. Now we're getting into a field I have a B. S. in, though it is a few decades out of date, and I've never heard of this.
More to the point though, Brownian motion happens because with sufficiently small objects, the random impacts from molecules will, for a short period of time, come more from one direction than another, resulting in a random jiggling. I'm pretty sure humber's claim is something he just pulled out of his posterior, as I cannot see any way that the shape of an object could make any difference in the momentary unbalance of random impacts. I'm just a tiny bit unsure of this, so I hedged a little bit, and if humber can come up with a source that actually supports this claim, I'm prepared to change my mind.
According to he who must not be contradicted, work = force, so why shouldn't velocity = speed? Or weight = temperature? Or voltage = distance ........
-- Roger
I tell you what, I will have the Queen notified that you may be in the tentative position of.....
changing your mind
Getting motion from molecular motion is not related to Maxwell's Deamon.
Think surface tension. Surface energy.
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Then what will satisfy you? A note from The Queen?
It is RMS, and that mean YOU ARE WRONG: live with it.
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