Author Topic: EM Drive Developments - related to space flight applications - Thread 5  (Read 779338 times)

Offline OnlyMe

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And the results are in: resonance at 2.4959 GHz with a Q of 8155.   It works!

Deriving the mode shape will take a bit more work.

So the question now is how the quartz rod affects resonance and Q.

Online aero

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Except I have already achieved Q > 20,000.

What bandwidth and resolution did you use?
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Offline ThereIWas3

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Resolution was 100.  Runtime was 1 hour.  No symmetry optimization.  BW was whatever was in the original NSF-1701.ctl file;  I have not touched it.
"If you want to build a ship, don’t drum up people to collect wood and don’t assign them tasks and work, but rather teach them to long for the endless immensity of the sea" - Antoine de Saint-Exupéry

Online aero

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Resolution was 100.  Runtime was 1 hour.  No symmetry optimization.  BW was whatever was in the original NSF-1701.ctl file;  I have not touched it.

Oh, I see. Except that I don't know what your BW is either. Maybe you could search your control file for the parameter
" BW ", that is, BW with leading and trailing spaces, and tell us what it is set to. And are you running NSF-1701 model or are you running Shell's dimensions?

My Q = 20,146   at frequency = 2.46554 was Shell's model at resolution = 100 and bandwidth = 0.05 * 2.47 GHz. Drive was 2.47 GHz.
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Offline Rodal

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Resolution was 100.  Runtime was 1 hour.  No symmetry optimization.  BW was whatever was in the original NSF-1701.ctl file;  I have not touched it.

Oh, I see. Except that I don't know what your BW is either. Maybe you could search your control file for the parameter
" BW ", that is, BW with leading and trailing spaces, and tell us what it is set to. And are you running NSF-1701 model or are you running Shell's dimensions?

My Q = 20,146   at frequency = 2.46554 was Shell's model at resolution = 100 and bandwidth = 0.05 * 2.47 GHz. Drive was 2.47 GHz.

When I run Shell's a long time ago I got quality of resonance around Q ~ 80,000 with a transverse electric mode  but that was with Shell's geometry at that time, using spherical ends (at the time that I was also posting the stresses).
« Last Edit: 12/11/2015 01:31 AM by Rodal »

Offline Fugudaddy

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...and mankind dreamed of nearly unlimited energy:
The first plasma: the Wendelstein 7-X fusion device is now in operation
http://www.ipp.mpg.de/3984226/12_15

It isn't a well tuned microwave, but what was once seriously unattainable is becoming closer to reality.

Yes, I know y'all skeptics... Fusion is a long well understood science that we've not had the technology to develop and that's different than this.

Mankind put in over a million hours of work on that piece of machinery to make microscopic suns that last a half an hour then die.

People like to build. There's a lot of people on this forum that *really* like to build. I have an odd tickling that says that maybe what their tinkering with has the potential to be something fascinating. If you don't believe it; great. There's room for skeptics and necessary room as well. Nobody learns a thing if everybody is rah-rah'ing everything.

There's more than a handful of people here who have been following this thread from Dr. Rodal's article back nearly six months ago; and who are still following it to see where this goes. This is drama at the edge of human understanding. Busted or Confirmed, the search to figure out what's going on has been a fascinating one. I wholeheartedly encourage those who are building to keep it up. :D

Be excellent to each other.

Offline ThereIWas3

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Sorry, I was not at my desk before.  Here are all the parameters I used:

Frustrum dimension that SeeShells told me to use: L=0.2479m Big=0.295m Small=0.170m
Flat end-plates, 8/32" thick.  Permittivity of Copper: -2*pi*2.4GHz*3.252698E+8i

Center frequency of the gaussian noise pulse, 2.47 GHz.  BW used by the harminv search algorithm, 0.025*F

"If you want to build a ship, don’t drum up people to collect wood and don’t assign them tasks and work, but rather teach them to long for the endless immensity of the sea" - Antoine de Saint-Exupéry

Offline ThereIWas3

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Looking back at the number I see I misread the spreadsheet.  The reported Q for Shell's model was negative 8937.  Something is wrong.
"If you want to build a ship, don’t drum up people to collect wood and don’t assign them tasks and work, but rather teach them to long for the endless immensity of the sea" - Antoine de Saint-Exupéry

Offline JonathanD

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...and mankind dreamed of nearly unlimited energy:
The first plasma: the Wendelstein 7-X fusion device is now in operation
http://www.ipp.mpg.de/3984226/12_15

It isn't a well tuned microwave, but what was once seriously unattainable is becoming closer to reality.

Yes, I know y'all skeptics... Fusion is a long well understood science that we've not had the technology to develop and that's different than this.

Mankind put in over a million hours of work on that piece of machinery to make microscopic suns that last a half an hour then die.

People like to build. There's a lot of people on this forum that *really* like to build. I have an odd tickling that says that maybe what their tinkering with has the potential to be something fascinating. If you don't believe it; great. There's room for skeptics and necessary room as well. Nobody learns a thing if everybody is rah-rah'ing everything.

There's more than a handful of people here who have been following this thread from Dr. Rodal's article back nearly six months ago; and who are still following it to see where this goes. This is drama at the edge of human understanding. Busted or Confirmed, the search to figure out what's going on has been a fascinating one. I wholeheartedly encourage those who are building to keep it up. :D

Be excellent to each other.

Awesome.  And compared to the cost of ITER?  Sigh, don't get me started.  It is OT but it's hard not to get jazzed about it. 

For heavy metal fans, I would think General Fusion would create quite a beat as well with all those pistons!

http://www.ted.com/talks/michel_laberge_how_synchronized_hammer_strikes_could_generate_nuclear_fusion 

Offline zen-in

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Looking back at the number I see I misread the spreadsheet.  The reported Q for Shell's model was negative 8937.  Something is wrong.

A Q=0 means no energy is stored.   A negative Q means energy is materializing inside the cavity.   I don't believe that is possible. 

Offline RotoSequence

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Looking back at the number I see I misread the spreadsheet.  The reported Q for Shell's model was negative 8937.  Something is wrong.

A Q=0 means no energy is stored.   A negative Q means energy is materializing inside the cavity.   I don't believe that is possible.

That would be a handy explanation for the anomalous thrust and Eagleworks' interferometry research if it wasn't clearly wrong, though.  ;D
« Last Edit: 12/11/2015 03:28 AM by RotoSequence »

Online aero

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Looking back at the number I see I misread the spreadsheet.  The reported Q for Shell's model was negative 8937.  Something is wrong.

A Q=0 means no energy is stored.   A negative Q means energy is materializing inside the cavity.   I don't believe that is possible.

That would be a handy explanation for the anomalous thrust and Eagleworks' interferometry research if it wasn't clearly wrong, though.  ;D

Meep calculates Q using the formula Q = -Re(w) / 2 * Im(w)   so what is wrong is that the run has terminated when  Im(w), which would like to be zero has became positive. A numerical artefact in other words, undesirable though it may be.
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Online aero

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Sorry, I was not at my desk before.  Here are all the parameters I used:

Frustrum dimension that SeeShells told me to use: L=0.2479m Big=0.295m Small=0.170m
Flat end-plates, 8/32" thick.  Permittivity of Copper: -2*pi*2.4GHz*3.252698E+8i

Center frequency of the gaussian noise pulse, 2.47 GHz.  BW used by the harminv search algorithm, 0.025*F

We still need to know the resolution you used. --- Sorry, I see you posted that before.

And what is the calculated value of the parameter CU-D-conduct? Just print it from the control file.
If you're using different names, then I am asking about the numerical value of D-conductivity in your material instruction.
« Last Edit: 12/11/2015 04:01 AM by aero »
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Online aero

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Resolution was 100.  Runtime was 1 hour.  No symmetry optimization.  BW was whatever was in the original NSF-1701.ctl file;  I have not touched it.

Oh, I see. Except that I don't know what your BW is either. Maybe you could search your control file for the parameter
" BW ", that is, BW with leading and trailing spaces, and tell us what it is set to. And are you running NSF-1701 model or are you running Shell's dimensions?

My Q = 20,146   at frequency = 2.46554 was Shell's model at resolution = 100 and bandwidth = 0.05 * 2.47 GHz. Drive was 2.47 GHz.

When I run Shell's a long time ago I got quality of resonance around Q ~ 80,000 with a transverse electric mode  but that was with Shell's geometry at that time, using spherical ends (at the time that I was also posting the stresses).

Yes, I remember that. That is one of the reasons I'm not finished with my convergence check on Q.
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Offline Rodal

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Looking back at the number I see I misread the spreadsheet.  The reported Q for Shell's model was negative 8937.  Something is wrong.
Was the conductivity you used in your input a negative or positive number ?

Offline Rodal

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Looking back at the number I see I misread the spreadsheet.  The reported Q for Shell's model was negative 8937.  Something is wrong.

A Q=0 means no energy is stored.   A negative Q means energy is materializing inside the cavity.   I don't believe that is possible.

That would be a handy explanation for the anomalous thrust and Eagleworks' interferometry research if it wasn't clearly wrong, though.  ;D
It is very positive that a negative Q is immediately recognized as something wrong and not as a manifestation of negative mass, dark energy, dark masss, or something else not present in Meep's formulation.

We will fix this.  It is very positive that we have more people running Meep.
« Last Edit: 12/11/2015 12:18 PM by Rodal »

Offline SeeShells

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Looking back at the number I see I misread the spreadsheet.  The reported Q for Shell's model was negative 8937.  Something is wrong.

A Q=0 means no energy is stored.   A negative Q means energy is materializing inside the cavity.   I don't believe that is possible.

That would be a handy explanation for the anomalous thrust and Eagleworks' interferometry research if it wasn't clearly wrong, though.  ;D
It is very positive that a negative Q is immediately recognized as something wrong and not as a manifestation of negative mass, dark energy, dark masss, or something else not present in Meep's formulation.

We will fix this.  It is very positive that we have more people running Meep.

Yes, something is more than a little disconcerting with negative Q, in many ways. I'll be around if anyone needs any information on the build numbers.

(Meepers, do we have the sidewalls correct and are we sure we are not leaking RF, if we don't use the tune chamber for the different tune points TE012 and TE013 and we just extend the Se top plate will leave a large gap.)

Shell





Offline ThereIWas3

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I did a little Googling and found that many meep users (not just here - everywhere) ran into the negative Q problem.  It is an artifact of the way meep works, and is an indication that the simulation did not run long enough.  Decreasing the bandwidth helps too.

After some other attempts, hunting around, I finally set BW to 0.015, set the center frequency to 2.4959 GHz where it wanted to resonate anyway, and increased the runtime by a factor of 1.25.  (aero: I did this by increasing 'gc' from 8 to 10)  Now I get a positive Q, that is closer to Rodal's earlier result.  I got Q=99,938.   Also absolute amplitude went up from 4.9 to 23.5.   Error is 4.12E-7.  Runtime was about 2 hours.  Resonant frequncy came out 2.4959-1.248E-5i.

The equation I used for CU-D-conduct (which is the imaginary part of the relative complex permittivity (I should change the variable name) was posted earlier, -2*pi*2.4GHz*3.252698E+8i.  That evaluates to -4.9083E+9.   The "2.4GHz" term is actually in "meep units" so it is 2.4E+9 times 'a' divided by 'c'.
"If you want to build a ship, don’t drum up people to collect wood and don’t assign them tasks and work, but rather teach them to long for the endless immensity of the sea" - Antoine de Saint-Exupéry

Offline Chris Bergin

Ok guys, new era with the next in the series of EM Drive threads:

Thread 6 - with a new moderation structure where a well known "EM Driver" is now the caretaker, not one of the regular mods.
http://forum.nasaspaceflight.com/index.php?topic=39004.0


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