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#2060 by Fabricatus on 21 Jan, 2016 05:54
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And where is this blue ribbon peer reviewed paper? It's been over 2 months since Paul March's post where he more or less acknowledges the anomalous thrust is a thermal phenomena when tested in a vacuum. If there really is an em-drive thrust at STP it won't be useful in outer space. The NASA EW program appears to be just fading away, like so many others.
First post from a long time lurker here, but I had to respond to this.
I work in a different specialism entirely (Bioinformatics) and I was involved in writing an oncology review a couple of years ago (I was a mid author). Even with prior acceptance from the journal, it took about 8 months for the paper to make it out the door. It would seem to me that in a field as controversial as this the peer reviewers and editors are going to be demanding a lot of evidence from the authors so they don't look like gullible fools, and its probable that there is a lot of back and forth between the journal and the writers as they tighten up the experimental evidence.
I am following this story with interest as I remember the original article in New Scientist that upset everyone and I want to see how it all ends. -
#2061 by zen-in on 21 Jan, 2016 07:46
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...
And where is this blue ribbon peer reviewed paper? It's been over 2 months since Paul March's post where he more or less acknowledges the anomalous thrust is a thermal phenomena when tested in a vacuum. If there really is an em-drive thrust at STP it won't be useful in outer space. The NASA EW program appears to be just fading away, like so many others.
Wow, I respectfully suggest you actually READ the material you quoted. Paul said the vacuum tests look "very thermally contaminated" but EW has come up with a tool "to help separate the EM-Drive thrust pulse waveform contributions from the thermal expansion cg induced baseline shifts of the TP". He does NOT acknowledge the anomalous thrust is a thermal phenomenon, neither "more or less".
I suggest you do not try to interpret what he says, but rather take it literally.
And as I've written before, even IF for some bizarre reason the EMDrive needed to be pressurized to work, so what? Pressurize it and run it in outer space. It's a closed frustum and nothing comes flowing out the back.
I interpret the statement "very thermally contaminated" to mean they see the vacuum test results are mostly from thermal effects. I don't know how else it could be interpreted, except that they don't know how much is from thermal expansion. I can certainly see how it is possible to separate any thrust from the thermal effect. Thrust will show up as a second order step response and thermal effects will show up as a first order step response. The two can be easily distinguished. I have already shown how the "thrust" data from EW's vacuum tests very closely matches an exponential curve. That is enough proof for me to say it is all thermal. Maybe if they run multiple tests and are able to co-add the data a second order step response will appear. But I kind of doubt it...First post from a long time lurker here, but I had to respond to this.
I work in a different specialism entirely (Bioinformatics) and I was involved in writing an oncology review a couple of years ago (I was a mid author). Even with prior acceptance from the journal, it took about 8 months for the paper to make it out the door. It would seem to me that in a field as controversial as this the peer reviewers and editors are going to be demanding a lot of evidence from the authors so they don't look like gullible fools, and its probable that there is a lot of back and forth between the journal and the writers as they tighten up the experimental evidence.
I am following this story with interest as I remember the original article in New Scientist that upset everyone and I want to see how it all ends.
Welcome to the forum. I agree it does take time to write a good paper. But we haven't seen anything new from EW since July 2014. Correct me if I am wrong. -
#2062 by oliverio on 21 Jan, 2016 10:12
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@zen-in:
I do believe you may be misinterpreting their results, and I mean no offense at all by that. However, consider this:
Air cooling is considered to be pretty efficient in the scheme of things; many rather robustly heated systems can be maintained by air cooling alone. Now, in a vacuum, the difference is essentially that we don't have a cool fluid constantly flowing over the surface of the frustrum...
With all that in mind a few things become clear:
1) it ought to be harder to account for buckling-type forces in a vacuum
2) if thermal buckling or expansion drive the frustrum out of resonance by route of changing geometry, there may be less force (if some resonance-force relation is assumed) in a vacuum test
3) the resonance of a cavity in air will not be quite the same as in vacuum, so there may have been modal issues at play as I do not believe the in-vacuum runs were checked for mode presence/stability [may be wrong here] -
#2063 by Rodal on 21 Jan, 2016 12:20
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I'd like to thank monomorphic, from another forum who put together a great comparison of most known emdrive cavities. Well done and thanks for sharing!
The same poster that posts on Reddit, that you thank in the above post (Monomorphic), reports that he is now running the complete, Full version of FEKOQuote from: MonomorphicI have FEKO full version up and running now
and is interacting with IslandPlaya to learn to model the EM Drive with FEKO software that (unlike Meep) allows the user to intuitively and rapidly digest the electromagnetic field information and current information in an intuitive way: providing numerical values in SI units in 3D for the truncted cone, as vector resultants instead of 6 different components. Hence rather than argue about mode shapes and people getting confused by incorrect interpretation of mode shapes, people can readily and rapidly agree as to what is going on (as TheTraveller and I recently agreed on mode shapes being shown by FEKO for SeeShell's fustrum excited by rectangular waveguides: showing transverse magnetic mode shape TM112 instead of the expected TE012).
As Monomorphic and others use the full version of FEKO, we look forward to more interesting modeling. For example, Zellerium and IslandPlaya are discussing the input of a magnetron's frequency spectrum in FEKO to model the resonance response of an EM Drive when excited by a magnetron (instead of being excited by single frequency excitation as modeled up to now).
___...In the FEKO sim his internal forces and modes were not symmetrical inside of the cavity.
https://drive.google.com/file/d/0B6juR48k_XoTbnNZT0NmcjBLVzQ/view
If this was the case, we might see a dampening effect on the natural oscillatory frequency of the DUT and fixture instead of the anticipated directional force.
Shell
* http://nextbigfuture.com/2015/11/nasa-eagleworks-has-tested-upgraded.html
I doubt that FEKO can calculate forces. Neither does Meep "out of the box" calculate forces or stresses. I post-processed the data output from Meep with Wolfram Mathematica, writing Mathematica code to calculate Maxwell's Stress Tensor, and integrated the Maxwell stress tensor components over the area to calculate forces vs. time, based on Meep output. All of that requires writing computer code to post-process the data.
Of course, for a completely closed cavity not interacting with other fields (as the EM Drive is conceived and being modeled), all such stresses, and therefore forces, should be perfectly equilibrated throughout the frustum of a cone, as the equations being solved (Maxwell's equations) are known to perfectly satisfy conservation of momentum and hence there cannot be such a thing as self-accelerating EM Drive according under such assumption.
So, the point of such an analysis (calculating stresses and forces based on Maxwell's equations) was to compare theoretical predictions vs. what is being discussed in several papers (for example the papers by Shawyer, Yang, Egan, etc.), particularly regarding the stress distribution in the cavity, vs. time, for different mode shapes and field excitation. It could also be useful to understand what experimental artifacts may be responsible for an anomalous force measurement (for example, when, as in experiments, the EM Drive is not "floating in space" but it is connected (or supported) by structural members that carry stresses and forces, and therefore have to be taken into account in the equation of equilibrium and in the boundary conditions).
Up to now, it is my understanding that such stresses and forces (taking together both the EM Drive and the supporting structure) have not been numerically analyzed. -
#2064 by rfmwguy on 21 Jan, 2016 13:16
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I agree Doc, the Fockers
have a lot to show once a responsible person starts learning the ins and outs. This will take more than a few days to understand and generate useful data. Agreed, don't think there are any models for stress forces directly...whodathunkit? Should the emdrive enigma be resolved, new factors would have to be added to standard electromechanical models. I nominate you to lead that effort (should this whole project turn out to be authentic). 
There is also notsureofit's hypothesis...I'd love to see that coded in an online software package we can tweak as we move forward. I got the domain http://rfdriven.com for Glenn to play with on his own servers, he might be more than happy to add a page or two for this on-line calculator.
WarpTech can hopefully return and add his own mix to the emdrive software. TT has his own spreadsheet...perhaps that's a decent place to start.
I'd also welcome DeltaMassRev2 back to the forum as I always enjoyed his "anti-emdrive" critiques and chat about floobie sticks. -
#2065 by Rodal on 21 Jan, 2016 13:56
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I received Personal Messages asking me: "why is it that you continue to point out that the mode shape calculated by FEKO for SeeShells with a waveguide is TM112 instead of TE012? what difference does it make?"
ANSWER: The reason why this is important is that all three theories with predicting formulas for the EM Drive (Shawyer, McCulloch and Notsosureofit) essentially predict a force as follows (https://forum.nasaspaceflight.com/index.php?topic=39214.msg1474347#msg1474347) :
Force = Q * PowerForward * Factor
where "Factor" is a function dictated by the geometrical dimensions of the frustum of a cone and by the material properties of the medium filling the cavity, as well as the mode shape.
So, the "anomalous force" is a direct function of the quality factor "Q"
Now, it is well known that the quality factor is vastly different for mode shapes TE011 orTE012 and TM111 or TM112.
For example, for a cylindrical cavity one can readily show that (all other things being equal: geometry, filling medium and metal) the Q for a cavity having diameter equal to its length, is such that:
Q for TE011 is ~2.2 times greater than for TM111
Q for TE012 is ~2.7 times greater than for TM111
(See Collin's "Foundations for Microwave Engineering" p. 508 , Fig. 7.18)
In other words, all things being equal, the quality factor for mode shapes TE011, TE012, TE013, etc. is much greater than for mode shape TM111, TM112, etc.
And since the force is supposed to be proportional to the Q, one would expect a greater force, according to these theories using mode shapes TE011, TE012, TE013 etc.
This is important because the "anomalous force" is so small that many times is below the noise threshold of other effects like thermal effects. Lorentz forces, etc.
Also, notice that Yang reports to have used mode shape TE012 for her experiments that claim the highest forces ever measured for an EM Drive, and that Shawyer appears to have used mode shapes TE012 and TE013 for his Demonstrator and FlightThruster, respectively.
On the other hand, Paul March at NASA reports that Dr. White's Quantum Vacuum theory does not have such a straigthforward relationship with Q, and that's why NASA uses TM212 mode shape instead of TE012.
(Although if you look at NASA's experimental data http://emdrive.wiki/Experimental_Results and report you will notice that also NASA reported the highest Force/Power for mode shape TE012 as well).
Also notice that NASA's reported anomalous force has only occured when inserting dielectric rings at the small end and that NASA reported NO anomalous force when not using dielectric inserts.
_________
Bottom line: if the mode shape excited in SeeShell's experiment is TM112 as predicted by FEKO instead of TE012 then her Q maybe 2.7 times smaller than it could have been with mode shape TE012 and hence according to these theories, the force may also be 2.7 times smaller than what it could have been otherwise and hence it may be more difficult to distinguish from thermal effects and Lorentz forces, according to these theories. -
#2066 by sghill on 21 Jan, 2016 14:10
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Sorry, I am not likely to be spending much more time on this effort other than to write a summary paper. At this point the "EmDrive" at DIY level is obviously just an RF playground. There is literally zero credible evidence that any experiment to date has produced any abnormal force anywhere above the noise level. Note the word credible above, as it is simply unbelievable to what extremes people are willing to bend and massage the facts in order to
keep the illusion alive, stay in business, get more fundingwhatever their agenda is. This was a fun exercise in RF techniques, but even more so this was just another sad encounter with human nature.
Fair enough. I'm impatient for news too, but then I think back to these two posts from Paul March that keep me coming back for more:
http://forum.nasaspaceflight.com/index.php?topic=38577.msg1441183#msg1441183
"CW:
"If...the new particle pair momentum gained, gets merged back into spacetime or quantum vacuum as a superset, it seems likely that this would lead to spacetime locally gaining momentum itself. Space gaining unidirectional momentum would then be equivalent to spacetime having gotten accelerated. In this picture, space itself would start to move away from the QV-thruster 'nozzle', while the QV-thruster would experience the opposite acceleration."
Bingo! If Dr. White is correct in arguing that 4D+ spacetime IS the quantum vacuum and visa versa, and if gravity is an emergent force generated by the forced hydrodynamic flow of the quantum vacuum, then what these EM-Drives are, is a directional "gravity" flow generator powered by E&M fields. The trick now is to prove this conjecture, which at a minimum will take the final marriage of Quantum Mechanics (QM) and General Relativity Theory (GRT)...
BTW, IF QV spacetime flow is the root cause of the phenomenon we call gravity generated by mass, IMO there has to be at least one more spatial dimension beyond our normally perceived 3D universe to provide this QV gravity flow a "drain" back into the universal QV reservoir. If you read the EW Lab's Bohr atom paper over at the NASA NTRS file server that I pointed to last night, you will note the 1/r^4 force dependency with distance of the Casimir force. If you delve deeper into why this is so, you will find that this 1/r^4 force dependency requires an n+1 spatial dimension system or a 5d+time (6D) universe. "
Coupled with this message:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1361931#msg1361931
"Dr. Rodal:
QUESTION 1: Is it correct to assume that the assessment of the interferometer path-length-change measurements was accomplished by looking at the Power Spectral Density at an anomalous frequency high enough away from the pink noise area (system 1/f noise, quantum 1/f noise etc.), and so clearly distinguishable from system noise occurring at frequencies close to zero?
Yes it is for its around 0.660 seconds
QUESTION 2: If so, did the observed anomalous peak in the Power Spectral Density occur at a frequency in accordance with the time taken to energize and de-energize?
Yes, the on/off cycle time was around 1.5 seconds with some uncertainty due to Windows 7.0 time outs. Need a real time operating system (RTOto clear that problem, a RTOS system we don't have.
QUESTION 3: Did you plot three dimensional plots to look for power peak distribution distributions looking like ring-shaped circular-waves, corresponding to path length changes associated with such frequency (in question2) ?
Yes, see attached picture.
QUESTION 4: Did you conduct additional tests to confirm repeatibility of the measurements?
Yes Michael Rollins performed four additional 27,000 on/off data sets under the same 30W RF drive condition and obtained similar test results for all five cases. Mind you at 20W RF input there was only a hint of the space-time compression effect visible above the noise platform.
QUESTION 5: One would expect such ring-waves to display some statistical distribution, therefore using measures of central tendency like different truncated mean measures ( http://en.wikipedia.org/wiki/Truncated_mean ) of the multidimensional power spectral density data may be particularly helpful in assessing the data (at least I have found so in assessing massive data for different problems that also involve 1/f noise)
I will point that out to Dr. White tomorrow.
QUESTION 6: Has NASA Eagleworks addressed the issue with air refraction raised in this paper by Lee and Cleaver from Baylor University?:
http://arxiv.org/ftp/arxiv/papers/1407/1407.7772.pdf
In particular, has NASA Eagleworks assessed the likelihood of the path-length-change measurements being the result of transient air heating ?
See Dr. White's preliminary assessment of that issue in the attached slide. Ultimately though we will be running the warp-field resonant cavity with a vacuum contained in its active volume to get rid of all possibilities of air heating problems.
Best, Paul M."
My point of posting these two above messages from Mr. March is that even if no thrust is presently being detected, their interferometer detected "non-negative" signs of changes in spacetime (the laser beam path length changed) within their various cavities when the things are turned on. Even without thrust, they may be seeing something that is well beyond a simple RF curiosity. Successfully manipulating a gravity flow in a preferential direction (instead of straight "in" like any massive body at rest, or warped around itself like any massive body that is spinning) within an EMDrive's frustrum will create momentum without violating CoM. But this post is covering ground we covered in 2014 and early 2015....
BTW, Paul March stated in November that the EW peer-reviewed paper was not expected to be released no earlier than the first HALF of 2016. http://forum.nasaspaceflight.com/index.php?topic=38577.msg1441094#msg1441094
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#2067 by Mulletron on 21 Jan, 2016 14:34
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https://www.authorea.com/users/58765/articles/77812
Looks like this is a work in progress. It's about Eagleworks. -
#2068 by TheTraveller on 21 Jan, 2016 14:39
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(See Collin's "Foundations for Microwave Engineering" p. 508 , Fig. 7.18)
Interesting statement from page 506 (some editing to clean up scanning errors) that should be of interest to Shell in regard to her end plate tuning scheme.QuoteOf particular interest is the TE01 mode for wavemeters because its Q is two to three times that of the TE11 mode.
Another advantage of the TE01 mode is that H = 0, and hence there are no axial currents.
This means that the end plate of the cavity can be free to move to adjust the cavity length d for tuning purposes without introducing any significant loss since no currents flow across the gap; i.e., the gap between the circular end plate and the cylinder wall is parallel to the current flow lines.
However, the TE01 mode is not the dominant mode; so care must be exercised to choose a coupling scheme that does not excite the other possible modes that could resonate within the frequency tuning range of the cavity. -
#2069 by Rodal on 21 Jan, 2016 14:40
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https://www.authorea.com/users/58765/articles/77812
Looks like this is a work in progress. It's about Eagleworks.
I found this website for the author:
http://crockpotveggies.com/
http://crockpotveggies.com/2015/06/12/whats-missed-nasa-warp-research.html -
#2070 by Notsosureofit on 21 Jan, 2016 14:44
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https://www.authorea.com/users/58765/articles/77812
Looks like this is a work in progress. It's about Eagleworks.
Just passing through..
? Do you remember, offhand, how much phase shift White observed ?
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#2071 by SeeShells on 21 Jan, 2016 14:51
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I received Personal Messages asking me: "why is it that you continue to point out that the mode shape calculated by FEKO for SeeShells with a waveguide is TM112 instead of TE012? what difference does it make?"
ANSWER: The reason why this is important is that all three theories with predicting formulas for the EM Drive (Shawyer, McCulloch and Notsosureofit) essentially predict a force as follows (https://forum.nasaspaceflight.com/index.php?topic=39214.msg1474347#msg1474347) :
Force = Q * PowerForward * Factor
where "Factor" is a function dictated by the geometrical dimensions of the frustum of a cone and by the material properties of the medium filling the cavity, as well as the mode shape.
So, the "anomalous force" is a direct function of the quality factor "Q"
Now, it is well known that the quality factor is vastly different for mode shapes TE011 orTE012 and TM111 or TM112.
For example, for a cylindrical cavity one can readily show that (all other things being equal: geometry, filling medium and metal) the Q for a cavity having diameter equal to its length, is such that:
Q for TE011 is ~2.2 times greater than for TM111
Q for TE012 is ~2.7 times greater than for TM111
(See Collin's "Foundations for Microwave Engineering" p. 508 , Fig. 7.18)
In other words, all things being equal, the quality factor for mode shapes TE011, TE012, TE013, etc. is much greater than for mode shape TM111, TM112, etc.
And since the force is supposed to be proportional to the Q, one would expect a greater force, according to these theories using mode shapes TE011, TE012, TE013 etc.
This is important because the "anomalous force" is so small that many times is below the noise threshold of other effects like thermal effects. Lorentz forces, etc.
Also, notice that Yang reports to have used mode shape TE012 for her experiments that claim the highest forces ever measured for an EM Drive, and that Shawyer appears to have used mode shapes TE012 and TE013 for his Demonstrator and FlightThruster, respectively.
On the other hand, Paul March at NASA reports that Dr. White's Quantum Vacuum theory does not have such a straigthforward relationship with Q, and that's why NASA uses TM212 mode shape instead of TE012.
(Although if you look at NASA's experimental data http://emdrive.wiki/Experimental_Results and report you will notice that also NASA reported the highest Force/Power for mode shape TE012 as well).
All these things are true Dr. Rodal, but don't fail to realize that I have a tune chamber and can call out several modes through tuning, I can also vary my antenna waveguide injection, phase settings, and RF power levels.
These are the cavity dims I offered out to IslandPlaya on Reddit because he asked and
this is the the shortest distance I can excite and still leave the top small plate in the tune chamber with the waveguides configured as they are.
Currently working to see if I can get a full working copy of FEKO for a limited time, they seem willing to work with me on this. I want to give IslandPlaya credit for running some of my cavity dimensions. Although it's tough working through someone else to get all things correct in your build when they are just learning FEKO. In communication with a representative of the software and found out out a one year licensed version is $15,000 for 1-4 CPUs in the US. YMMV in other countries and licences.
Shell
Added: Frank Davies work on resonate modes, of note is the jumble of them through 2.45GHz.
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#2072 by Rodal on 21 Jan, 2016 14:52
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https://www.authorea.com/users/58765/articles/77812
Looks like this is a work in progress. It's about Eagleworks.
This is interesting (from http://crockpotveggies.com/ )QuoteOur interest in this gravitational research triggered a tangent where we looked closer at the original 1962 paper above. Quoted directly, "From general relativity follows also the possibility of the inverse conversion of gravitational waves into light waves, but this problem is hardly of interest."
Remember that in the Superfluid theory of the Quantum Vacuum, one can have light waves as well as gravitational waves (and there is a "second sound" related to thermal effects, due to entropy/temperature fluctuations instead of pressure/density fluctuations)
See: https://forum.nasaspaceflight.com/index.php?topic=38996.msg1469131#msg1469131 -
#2073 by Mulletron on 21 Jan, 2016 15:04
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If only the Gertsenshtein effect (electromagnetic waves to gravitational waves) and the inverse were confirmed, but I see no evidence of experimental confirmation.
@Notsosureofit, I don't remember off hand, maybe in reference 11 here https://en.m.wikipedia.org/wiki/White%E2%80%93Juday_warp-field_interferometer -
#2074 by Rodal on 21 Jan, 2016 15:06
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...
That would make the ability to model your EM Drive cavity with a program like FEKO, COMSOL, or ANSYS all the more important, because the shape of your EM Drive will not longer be a perfect truncated cone, as you add the cylindrical adjustable portion.
All these things are true Dr. Rodal, but don't fail to realize that I have a tune chamber and can call out several modes through tuning, I can also vary my antenna waveguide injection, phase settings, and RF power levels.
These are the cavity dims I offered out to IslandPlaya on Reddit because he asked and
this is the the shortest distance I can excite and still leave the top small plate in the tune chamber with the waveguides configured as they are.
Currently working to see if I can get a full working copy of FEKO for a limited time, they seem willing to work with me on this. I want to give IslandPlaya credit for running some of my cavity dimensions. Although it's tough working through someone else to get all things correct in your build when they are just learning FEKO. In communication with a representative of the software and found out out a one year licensed version is $15,000 for 1-4 CPUs in the US. YMMV in other countries and licences.
Shell
Added: Frank Davies work on resonate modes, of note is the jumble of them through 2.45GHz.
That's the beauty of using a program where you don't have to fight or get a headache by spending long hours trying to decipher what mode shape is being excited from having to read 6 different components expressed in Cartesian coordinates. With a program like FEKO, COMSOL, or ANSYS the mode shape is intuitive, out of the box, so you spend your time investigating "what if scenarios"
This may save a lot of experimentation time, as otherwise you will have to rely on a laborious time-consuming exercise of reading your thermal camera, then interpreting the thermal camera results in terms of what the eddy current heating of the end plate due to the magnetic field looks like. And you are never assured that you will be able to excite a TE012 or such mode, as the TE012 is more difficult to excite than the TM112 mode, as known in the literature. As Collin points out: the TE012 mode is not the dominant mode. TM112 is the dominant mode. As Collin shows, the mode chart, frequency vs dimensions, is identical for TE012 and TM112 for a cylindrical cavity (they become different for a truncated cone, but the truncated cones of the EM Drives being tried up to now are almost cylindrical because they keep the small end diameter similar in size to the big end). So as TheTraveller pointed out, one better excites TE012 by careful coupling.
Apparently there are other people running FEKO, so they may also be willing to run your geometry. The more independent verification you get the more sure you can be of the reliability of the modeling.
It is also interesting that they are looking at modeling the frequency spectrum of the magnetron as an input and that they are able to readily plot the S-parameter.
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#2075 by Rodal on 21 Jan, 2016 15:30
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More on excitation of TE012: it was so difficult to excite TE012 for NASA, even with COMSOL finite element modeling capabilities, that although NASA got the highest force/power for the TE012 experiment they switched to TM212.
When we asked Paul March in previous threads why did they stop using TE012 he essentially answered that they had lots of trouble being able to excite TE012 on a consistent basis. They were using a loop antenna.
Yes, they did not have an adjustable end, maybe that can help. One wonders how Shawyer and Yang can be sure of what mode they excited since they did not report using any thermal camera measurement... -
#2076 by SeeShells on 21 Jan, 2016 15:45
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More on excitation of TE012: it was so difficult to excite TE012 for NASA, even with COMSOL finite element modeling capabilities, that although NASA got the highest force/power for the TE012 experiment they switched to TM212.
When we asked Paul March in previous threads why did they stop using TE012 he essentially answered that they had lots of trouble being able to excite TE012 on a consistent basis. They were using a loop antenna.
Yes, they did not have an adjustable end, maybe that can help. One wonders how Shawyer and Yang can be sure of what mode they excited since they did not report using any thermal camera measurement...
One of the things meep got right was when we used a single antenna placed like EagleWorks to excite the cavity was a Betty Crocker Blender of rotating modes and poynting vectors. Symmetry is the key to locking in a mode along with the correct injection ports and location.
It puts doubt that the quoted modes of excitement were excited without any verifying data from thermal imaging. Thermal imaging is critical to assure you are indeed exciting the correct modes and backed up by computer modeling.
Shell
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#2077 by TheTraveller on 21 Jan, 2016 15:45
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One wonders how Shawyer and Yang can be sure of what mode they excited since they did not report using any thermal camera measurement...
Roger told me they inserted a wire loop probe and moved it around inside the frustum to confirm mode.
He also advised to design the frustum dimensions, coupler type and location/alignment to get optimal isolation from nearby undesired modes.
More Microwave Black Arts that FEKO may help turn into solid enginerring practice. -
#2078 by Rodal on 21 Jan, 2016 15:53
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One wonders how Shawyer and Yang can be sure of what mode they excited since they did not report using any thermal camera measurement...
Roger told me they inserted a wire loop probe and moved it around inside the frustum to confirm mode.
...
That's good to know. That's an old-fashioned, proven way to know what is going on inside the cavity. Sounds good if they know where the wire is at a particular moment in time.
They may have had multiple entry ports to be able to inspect what was going on inside the cavity. -
#2079 by aero on 21 Jan, 2016 16:39
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Has anyone taken a detailed look at CSC-Elmer?
https://www.csc.fi/web/elmer/elmer
I understand that it is a lot like COMSOL, difference being that CSC-Elmer is public domain.
have a lot to show once a responsible person starts learning the ins and outs. This will take more than a few days to understand and generate useful data. Agreed, don't think there are any models for stress forces directly...whodathunkit? Should the emdrive enigma be resolved, new factors would have to be added to standard electromechanical models. I nominate you to lead that effort (should this whole project turn out to be authentic). 