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Author Topic: Do transverse and longitudinal acoustic waves exchange momentum with one anotehr  (Read 2707 times)

Offline Phractality

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Exchange momentum between transverse and longitudinal acoustic waves is a cornerstone of my cosmology, but I know of no evidence that it is true. I've never even heard of anyone else's conjecture that it might be true.

I am interested in acoustic waves in foamy media, and in particular the foamy structure of the cosmos. I'm seeking a mainstream answer to a straightforward physics problem, which is why I'm posting in the mainstream forum. I can't go into much detail about why I need this information; that must be discussed in New Theories.

Imagine a longitudinal wave moving right to left across the page and a transverse wave moving from bottom to top. The plane of polarity of the transverse wave is parallel to the page.

The top of the transverse wave is a motion of the medium right to left, the middle of the transverse wave is moving left to right, and the bottom of the transverse wave is a motion of the medium right to left, back to its initial position.

The longitudinal wave moves the medium first left to right and then right to left, back to its original position.

When the two wave pass thru one another, the part of the longitudinal wave which passes thru the top part of the transverse wave encounters an extremely minute tailwind, and the part that passes thru the bottom of the transverse wave encounters an extremely minute headwind. Consequently, the longitudinal wave emerges from the collision very slightly twisted; its top part is now slightly ahead of its lower part.



I don't know if that twisting of the longitudinal wave changes the direction of its momentum vector, but I'm betting that is the case. As I said, the effect is extremely small, but for my purposes one part in 10^50 might be sufficient to power everything in the universe.

The postulated effect would be extremely difficult to simulate and measure in a laboratory using a chemical foam medium. Also, chemical foams with gas-filled bubbles are distinctly different from the foamy structure of the cosmos with its vacuum-filled bubbles (giant voids up to 100 million light years across). I think only a computer simulation can provide the answer. Furthermore, such a simulation would suffer from a lack of understanding of the dynamics of the cosmic foam. We don't really know what forces hold galaxies and dark matter together.

Please don't ask for details of my cosmology in the mainstream forum. This thread is only about exchange of momentum between longitudinal waves and transverse waves.




 

Offline Soul Surfer

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The fundamental problem with your thinking is that transverse waves only exist in materials with rigidity that is solids or the fields that are involved in quantum field theory.  This of course includes gravitational waves.

Liquids, gases and possibly (largely non colliding) gravitating bodies and particles do not have the required rigidity so transverse waves do not exist in them.

The forces holding normal and dark matter together are fully adequately explained by standard gravity so there is also no mystery here.
« Last Edit: 03/10/2012 12:22:49 by Soul Surfer »
 

Offline Phractality

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The fundamental problem with your thinking is that transverse waves only exist in materials with rigidity that is solids or the fields that are involved in quantum field theory.  This of course includes gravitational waves.

Liquids, gases and possibly (largely non colliding) gravitating bodies and particles do not have the required rigidity so transverse waves do not exist in them.

The forces holding normal and dark matter together are fully adequately explained by standard gravity so there is also no mystery here.

I believe the cosmic foam has sufficient rigidity to conduct transverse acoustic waves. The simple fact that it has structure suggests that it is neither gas nor liquid. I'm talking about wave lengths of hundreds of millions, or even billions, of light years. I believe such waves propagate via stresses in the structure of the foam.

If standard gravity were an adequate description of the forces among galaxies, why do we have so many new theories (such as this one; and MOND) trying to explain discrepancies between observations and the standard model? If rotating galaxies have net electric charges, there must be magnetic forces between them.

But this thread is about whether there is evidence of exchange of momentum between longitudinal and transverse acoustic waves in foamy solids. I'll settle for a computer simulation, since the experimental evidence may be next to impossible to obtain.

P.S.: If moderators want to move this thread to New Theories, I have no objection. If there is mainstream support for what I'm suggesting, perhaps it is new to the mainstream.
 

Offline JP

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It would depend on the medium in which they're propagating and what type of interactions go on between transverse and longitudinal modes due to the medium's properties.  I know both types exist in seismology (P and S-waves), but I can't find much about their interaction.  In googling for that, I found that there has been a study of mixing in plasmas.  Unfortunately, I can't help you much with plasma physics, since I know very little about it, but there seems to be a lot of literature on transverse-longitudinal interactions in plasmas.
 

Offline Phractality

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Thanks, JP. The links that I have found, concerning interaction of L and T waves in turbulent plasma are encouraging, even though they are incomprehensible to me.

I think it is particularly important that they report nonlinear interactions. I expect to see nonlinear interaction of L and T acoustic waves in a foamy solid, also. The exchange of momentum should depend on the relationship between the L-wave's direction of motion and the T-wave's phase and polarity, as well as their relative wave lengths. To analyze the effect, you would have to simulate every possible combination of wavelengths, phase angles and polarity angles.

Then, you would have to look at how pairs of T-waves affect the amount of momentum that each other receives from a uniform background of L-wave white noise. I anticipate that the result will be a force of attraction or repulsion between the two T-waves, depending on their relative wave lengths and their phase and polarity angles relative to one another.

This sort of computer simulation is light years beyond my own ability and training.
 

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