No comparison of the Meep model fields vs experiments and other models (I had suggested the TM212 thermal experimental results and the COMSOL FEA analyis at NASA for comparison) has been performed, to my knowledge, concerning these issues.
If you think Meep is inadequate for this, then I will not waste any more time on it. I have no idea how Meep models could be validated to satisfy your questions.
Not a Meep problem. A problem with the model:
Please consider whether to interpret the extreme dependence on angle (1 degree ) as possibly due to a Meep numerical model issue and not necessarily as a real physical effect (not a Meep problem, but a Finite Difference Model problem). It may not relate to actual physical experiments.
<<how Meep models could be validated to satisfy your questions.>> A Meep model can be compared, for validation, (in this case the electromagnetic fields you are showing) against:
1) a known exact solution (for problems having an exact solution: ie for a cylindrical cavity, also exact solution for a truncated cone as shown for example by Greg Egan
http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html )
2) experimental data (for example TM212 mode captured by Thermal camera by NASA)
3) another numerical solution (for example I have suggested the fields calculated by COMSOL FEA by NASA as shown by Frank Davis for TM212 NASA frustum of a cone)
PS: I followed this advice, when I was showing the results for my exact solution using Mathematica (that differs a little from Greg Egan's) I compared it first to Egan (I passed
successfully), then to 3) Frank Davis COMSOL FEA ( I passed successfully for all the modes) and finally to 2) the experimental case for TM212.
I have to thank Paul March for providing the COMSOL FEA and thermal analysis results that make such validation possible.
Just scrolling through all the conversations here from the last few days and I am a little disappointed with the philosophical debates of good science, bad science, "my experience is x", "my experience is Y", "Shawyer is crazy", "academics and risk", arguing over semantics and how something was said, etc etc..... Like a massive intellectual pride based pissing contest.
Can I ask a major favor? Please continue to be committed to reporting data, discussing designs, and potential theories of operation. I think this forum needs to tone down the emotions and turn up the science. For the love of Einstein, don't let this become Reddit. All this back and forth detracts from the science.. Leave emotion and personal pride at the door.
Just MHO, I could be wrong, but its hard to continue to follow the thread when we have the multi message debates on she said/he said semantic based arguments.
That said, I am patiently awaiting SHELL's data, TT's data, and NASA reports.
Carry on.
Dr B
That's pretty well said Dr. B...lack of data and news does bring out the drama. However we do have 2 new diyers from asia, shell is reinforcing her design and she will have quite a bit of data to share. I will not rat her out but I can say it will be worth waiting for.
I will take your good advice, thanks. Now I must ban you...just kidding
...
3) Exponential growth of electromagnetic fields, nowhere close to stability
the reason for the exponential growth has not been adequately addressed.
...
This exponential growth of the magnetic field inside the frustrum made me think of inductors and capacitors. I was wondering if it is possible that the growth is related to filling a capacitor (the frustrum). Maybe at first the resistance to being filled with energy (magnetic fields) is low and with time as it fills up it levels off. Does it behave something like E[1-e^(-t/T)], or is it more like E[1-e^(-x^2)] <- double curve, or are we just seeing e^(x) with out any leveling off.
Ok it looks like you use the equation "B (exp(t/tau) " in the equation "A t +B (exp(t/tau) Sin [C t + D] + E" so the growth is exponential. Could it be that it will behave like E[1-e^(-x^2)] where the taylor expansion is "taylor(1-%e^(-x^2),[x,0,8]); = x^2-x^4/2+x^6/6-x^8/24 " so we have rapid growth at first that levels off at a later time? Sub in x^2-x^4/2 for exp(t/tau) for example.
i.e. Maybe there is some inductive resistance to overcome early on?
(I guess the early inductive resistance would be "getting current flowing" to add light to the cavity and the capacitor filling up would be the existing light in the cavity fighting against the pressure of the antenna to input more light.)
Since this thread is old, viewership large and interests range from the experimental to the numerical to the theoretical and beyond (including the statistical, the psychological, the sociological and the philosophical), a number of people express dissatisfaction with its meandering ways from time to time. This one being one of those times
. It is natural. We have discussed in prior threads to split threads but the prior consensus was to keep it together. A reminder here that there are ways to filter information if one finds that there are too many posts for one's taste (or one's time). For example, let's say that you don't want to read Rodal's posts, or just cannot stand what Rodal has to say, then you can do the following:
1) Profile (upper menu in red, 5th from the left)
2) Modify Profile
3) Buddies/Ignore List
4) Edit Ignore List
5) Add to ignore list: Member "Rodal"
and "puff" you don't have to see Rodal's posts anymore
(relief at last
)
Since this thread is old, viewership large and interests range from the experimental to the numerical to the theoretical and beyond, a number of people express dissatisfaction with its meandering ways from time to time. This one being one of those times . It is natural. We have discussed in prior threads to split threads but the prior consensus was to keep it together. A reminder here that there are ways to filter information if one finds that there are too many posts. For example, let's say that you don't want to read Rodal's posts, or just cannot stand what Rodal has to say, then you can do the following:
1) Profile (upper menu in red, 5th from the left)
2) Modify Profile
3) Buddies/Ignore List
4) Edit Ignore List
5) Add to ignore list: Member "Rodal"
and "puff" you don't have to see Rodal's post anymore
I certainly wouldn't recommend that anyone do this. Dr. Rodal's contributions are some of the very best posts in these threads!
Thank your for confirming this most important information:
* Yang has retired
* Yang can NOT get recognition of the academic committee
* Yang has NO further project funding
* Yang's project grounded to a halt in 2014
* Yang cannot explain the conflict between her "theory" with existing physical theory
Seems you missed listing one item?
* Yang confirmed the results of the experiment
And also, while all this important information would certainly be unfortunate and discouraging if true, there is also a possibility that this is not the case at all. Yes, I know, conspiracy. Nobody likes it. Yet, imagine for the second that the effect has indeed been confirmed. And you're the military. What is your next step going to be? While the genie cannot be put back into the bottle, there is at least a chance to delay the recognition of the fact by every other country in the world. So report that it contradicts existing physics, and that nobody takes it seriously, and that the researcher has since retired (and nobody has heard anything back from her since then. How convenient.). Do not provide any details as to the actual results, and then just shut up expecting the hype to die off. I am not saying this is what is happening, there is no way to be sure of that; I am saying this would be a plausible scenario to pursue if the effect has actually been confirmed.
Well… to put it politely… this task turned out to be… umm… more difficult than I was hoping for. And after a day of struggling the result came out… ugly… At one point I was considering to give up, start from scratch and do it right. This would however imply a delay of at least a month… Figured I have nothing to lose with this one anyway, so I finished it the way I could.
…If I ever to do this again, or if anyone is planning to make one, the way to go is to order custom-made flanges for both ends; those would need to be made from ~3mm copper. Then cut the template and allow for the overlap joint (the way SeaShells did it). I went with a butt joint trying to avoid the 0.5 mm discontinuity; the resulting trouble is not worth it. The 2 flanges are a must to force the template into a proper circular shape and to then maintain that shape. Note how mine ended up deformed despite all the effort with steel ties.
Cleaning, tuning, characterizing (Q factor) and the actual test run will happen in early 2016. Makes for an easy New Year wish.
Happy coming New Year!
And also, while all this important information would certainly be unfortunate and discouraging if true, there is also a possibility that this is not the case at all. Yes, I know, conspiracy. Nobody likes it. Yet, imagine for the second that the effect has indeed been confirmed. And you're the military. What is your next step going to be? While the genie cannot be put back into the bottle, there is at least a chance to delay the recognition of the fact by every other country in the world. So report that it contradicts existing physics, and that nobody takes it seriously, and that the researcher has since retired (and nobody has heard anything back from her since then. How convenient.). Do not provide any details as to the actual results, and then just shut up expecting the hype to die off. I am not saying this is what is happening, there is no way to be sure of that; I am saying this would be a plausible scenario to pursue if the effect has actually been confirmed.
Have email Roger for his opinion. Last he told me was the Chinese had put a tight cap on the release of further data from Prof Yang.
Also emailed the poster and asked for more details such as photos of the test frustum, test rigs & unpublished test data.
If Prof Yang has retired and the poster did work with Prof Yang, would expect no one in China will get upset if more data is published.
What surprised me was the poster didn't know the Demonstrator rotary test rig videos were available on
www.emdrive.com Found that a bit strange.
Well… to put it politely… this task turned out to be… umm… more difficult than I was hoping for. And after a day of struggling the result came out… ugly… At one point I was considering to give up, start from scratch and do it right. This would however imply a delay of at least a month… Figured I have nothing to lose with this one anyway, so I finished it the way I could.
…If I ever to do this again, or if anyone is planning to make one, the way to go is to order custom-made flanges for both ends; those would need to be made from ~3mm copper. Then cut the template and allow for the overlap joint (the way SeaShells did it). I went with a butt joint trying to avoid the 0.5 mm discontinuity; the resulting trouble is not worth it. The 2 flanges are a must to force the template into a proper circular shape and to then maintain that shape. Note how mine ended up deformed despite all the effort with steel ties.
Cleaning, tuning, characterizing (Q factor) and the actual test run will happen in early 2016. Makes for an easy New Year wish.
Happy coming New Year!
What grade copper, hardness and thickness did you use?
I'm using 0.5mm (0.020") thick, soft, C110 for my cone. Waiting for my forming hoops to arrive to start my 1st build.
Plan is to use the hoops inside and outside the cone during the forming.
@TheTraveler
You wrote that 5 TC ~= 35 microseconds if I recall correctly. What cavity is that for, or is it generally accurate for all cavities operating at 2.45 GHz?
The reason I ask is that there have been a large number of meep runs generating data with the Yang-Shell 6 degree model for comparison. This model is likely the smallest, hence fastest running in meep that we have investigated in any detail. It is quite small because the big end diameter is substantially shorter than the it is on the other models. That means of course that running the Yang-Shell 6 degree model to 35 microseconds would be much quicker than the other models.
So the question, what do you suppose the TC is for the Yang-shell model?
(set! bigdia 0.201) ; ID - meters
(set! smalldia 0.1492) ; ID - meters
(set! high 0.24) ; meters - internal
@TheTraveler
You wrote that 5 TC ~= 35 microseconds if I recall correctly. What cavity is that for, or is it generally accurate for all cavities operating at 2.45 GHz?
The reason I ask is that there have been a large number of meep runs generating data with the Yang-Shell 6 degree model for comparison. This model is likely the smallest, hence fastest running in meep that we have investigated in any detail. It is quite small because the big end diameter is substantially shorter than the it is on the other models. That means of course that running the Yang-Shell 6 degree model to 35 microseconds would be much quicker than the other models.
So the question, what do you suppose the TC is for the Yang-shell model?
(set! bigdia 0.201) ; ID - meters
(set! smalldia 0.1492) ; ID - meters
(set! high 0.24) ; meters - internal
TC data is for a generic frustum with a Qu of 100k or Ql of 50k at 2.45 GHz
For your model I get:
Qu: 48.6k at 2.45 GHz
1 x TC: 3.155 usec
5 x TC: 15.775 usec
Transit time from end plate to end plate depends on excitation mode with TE012 (2 x 1/2 effective guide waves end to end stacked) being the same as the external driven frequency.
Transit time equation attached
…If I ever to do this again, or if anyone is planning to make one, the way to go is to order custom-made flanges for both ends; those would need to be made from ~3mm copper. Then cut the template and allow for the overlap joint (the way SeaShells did it). I went with a butt joint trying to avoid the 0.5 mm discontinuity; the resulting trouble is not worth it. The 2 flanges are a must to force the template into a proper circular shape and to then maintain that shape. Note how mine ended up deformed despite all the effort with steel ties.
What grade copper, hardness and thickness did you use?
I'm using 0.5mm (0.020") thick, soft, C110 for my cone. Waiting for my forming hoops to arrive to start my 1st build.
Plan is to use the hoops inside and outside the cone during the forming.
My copper is exactly the same
(20 mil, C110). With solid flanges at both ends it may only need a single outside hoop (or just a round of wire) in the middle to keep it circle. Solid end flanges are key though.
Thank your for confirming this most important information:
* Yang has retired
* Yang can NOT get recognition of the academic committee
* Yang has NO further project funding
* Yang's project grounded to a halt in 2014
* Yang cannot explain the conflict between her "theory" with existing physical theory
Seems you missed listing one item?
* Yang confirmed the results of the experiment
And also, while all this important information would certainly be unfortunate and discouraging if true, there is also a possibility that this is not the case at all. Yes, I know, conspiracy. Nobody likes it. Yet, imagine for the second that the effect has indeed been confirmed. And you're the military. What is your next step going to be? While the genie cannot be put back into the bottle, there is at least a chance to delay the recognition of the fact by every other country in the world. So report that it contradicts existing physics, and that nobody takes it seriously, and that the researcher has since retired (and nobody has heard anything back from her since then. How convenient.). Do not provide any details as to the actual results, and then just shut up expecting the hype to die off. I am not saying this is what is happening, there is no way to be sure of that; I am saying this would be a plausible scenario to pursue if the effect has actually been confirmed.
I'm worried that this entire argument (from the first Rodal post) is going to insult / drive off Chinese contributors. Might I suggest that we assume the information given is likely correct.
Well… to put it politely… this task turned out to be… umm… more difficult than I was hoping for. And after a day of struggling the result came out… ugly… At one point I was considering to give up, start from scratch and do it right. This would however imply a delay of at least a month… Figured I have nothing to lose with this one anyway, so I finished it the way I could.
…If I ever to do this again, or if anyone is planning to make one, the way to go is to order custom-made flanges for both ends; those would need to be made from ~3mm copper. Then cut the template and allow for the overlap joint (the way SeaShells did it). I went with a butt joint trying to avoid the 0.5 mm discontinuity; the resulting trouble is not worth it. The 2 flanges are a must to force the template into a proper circular shape and to then maintain that shape. Note how mine ended up deformed despite all the effort with steel ties.
Cleaning, tuning, characterizing (Q factor) and the actual test run will happen in early 2016. Makes for an easy New Year wish.
Happy coming New Year!
Wonder how the Q will compare to the Chinese frustum.
I'm worried that this entire argument (from the first Rodal post) is going to insult / drive off Chinese contributors. Might I suggest that we assume the information given is likely correct.
Have learned he/she has a TE013 molded frustum for sale.
Asking for more detailed engineering data.
@TheTraveler
You wrote that 5 TC ~= 35 microseconds if I recall correctly. What cavity is that for, or is it generally accurate for all cavities operating at 2.45 GHz?
The reason I ask is that there have been a large number of meep runs generating data with the Yang-Shell 6 degree model for comparison. This model is likely the smallest, hence fastest running in meep that we have investigated in any detail. It is quite small because the big end diameter is substantially shorter than the it is on the other models. That means of course that running the Yang-Shell 6 degree model to 35 microseconds would be much quicker than the other models.
So the question, what do you suppose the TC is for the Yang-shell model?
(set! bigdia 0.201) ; ID - meters
(set! smalldia 0.1492) ; ID - meters
(set! high 0.24) ; meters - internal
TC data is for a generic frustum with a Qu of 100k or Ql of 50k at 2.45 GHz
For your model I get:
Qu: 48.6k at 2.45 GHz
1 x TC: 3.155 usec
5 x TC: 15.775 usec
Transit time from end plate to end plate depends on excitation mode with TE012 (2 x 1/2 effective guide waves end to end stacked) being the same as the external driven frequency.
Transit time equation attached
Thank you for that. I'll see if I can estimate the run time to 15.775 usec simulated real time. After the current run completes.
Just scrolling through all the conversations here from the last few days and I am a little disappointed with the philosophical debates of good science, bad science, "my experience is x", "my experience is Y", "Shawyer is crazy", "academics and risk", arguing over semantics and how something was said, etc etc..... Like a massive intellectual pride based pissing contest.
Can I ask a major favor? Please continue to be committed to reporting data, discussing designs, and potential theories of operation. I think this forum needs to tone down the emotions and turn up the science. For the love of Einstein, don't let this become Reddit. All this back and forth detracts from the science.. Leave emotion and personal pride at the door.
Just MHO, I could be wrong, but its hard to continue to follow the thread when we have the multi message debates on she said/he said semantic based arguments.
That said, I am patiently awaiting SHELL's data, TT's data, and NASA reports.
Carry on.
Dr B
That's pretty well said Dr. B...lack of data and news does bring out the drama. However we do have 2 new diyers from asia, shell is reinforcing her design and she will have quite a bit of data to share. I will not rat her out but I can say it will be worth waiting for.
I will take your good advice, thanks. Now I must ban you...just kidding
Hahaha. Just trying to calm the discussion and point to the light to get to the good scientific bits I live for. I am hoping WarpDrive comes back and he and Dr. Rodal can make our brains spin again on theory discussions, those were the best moments in this thread (loved the limited frequency gravitation theory WarpDrive presented aka gravity in a can) Also looking forward to more data from yourself and Dr. Rodals continued MEEP interpretations
!!
Everyone keep on chugging, the answer will reveal itself soon.
DrB
And also, while all this important information would certainly be unfortunate and discouraging if true, there is also a possibility that this is not the case at all. Yes, I know, conspiracy. Nobody likes it. Yet, imagine for the second that the effect has indeed been confirmed. And you're the military. What is your next step going to be? While the genie cannot be put back into the bottle, there is at least a chance to delay the recognition of the fact by every other country in the world. So report that it contradicts existing physics, and that nobody takes it seriously, and that the researcher has since retired (and nobody has heard anything back from her since then. How convenient.). Do not provide any details as to the actual results, and then just shut up expecting the hype to die off. I am not saying this is what is happening, there is no way to be sure of that; I am saying this would be a plausible scenario to pursue if the effect has actually been confirmed.
Have email Roger for his opinion. Last he told me was the Chinese had put a tight cap on the release of further data from Prof Yang.
Just remember that for the above conspiracy to work it would not be just the Chinese
It would be everyone who knows the results first-hand... There is this thing called gag order...
Unfortunately at this point one can really only believe one's own experimental data.
I'm worried that this entire argument (from the first Rodal post) is going to insult / drive off Chinese contributors. Might I suggest that we assume the information given is likely correct.
Have learned he/she has a TE013 molded frustum for sale.
Asking for more detailed engineering data.
Yes ！ D - big: D - 290 mm small: 170 mm L - center: 240 mm TE013（pure copper sheet （ thickness 1.25 mm ））. If you need TE012, I can modify the mould.
successfully), then to 3) Frank Davis COMSOL FEA ( I passed successfully for all the modes) and finally to 2) the experimental case for TM212.