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#1680 by Rodal on 13 Jan, 2016 20:41
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I was contemplating an experiment where the frustum could be held at center mass, so that when it heats up the expansion of the mass would not induce a force of thrust.
...
Or if doing it in vacuum just suspend the frustum by center mass, but there is still thermal radiation effects so maybe the insulated sphere may still help.
My humble understanding is that suspending the frustum by center mass will not help with anything as its center mass is changing during the test, as frustum heating from RF induced currents is not at all uniform.
Look at all those images of COMSOL surface power dissipation. Here's one I posted for TE012:
But for axisymmetric mode shapes (as the one shown), the center of mass moves along the axis of axisymmetry of the truncated cone, so the idea still may be exploited (albeit to a reduced extent) as the center of mass only moves along one axis (out of three) for symmetric mode shapes. In this case all it means is that if the cone is hanged from the end of a balance, it should be hanged from the axis of axisymmetry of course, so that the distance to the fulcrum does not change.
In any case, good point you make, as Meep has revealed the existence of asymmetric mode shapes, and since Tajmar (advised by Roger Shawyer) fed his EM Drive asymmetrically with a waveguide from only one side resulting in side forces (Tajmar's cavity being thermally asymmetric !!!) in Tajmar's experiments. -
#1681 by RFPlumber on 13 Jan, 2016 21:27
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...
For example, the effect of natural thermal air convection from the fustrum with vortex shedding and Navier Stokes equation in a low Reynolds number regime above Stokes flow cannot be understood by experimenters, there has not been any Computational Fluid Dynamics of it, or visual study of it in slow motion, or experimental profiling of the air convection (no smoke, tufts, evaporating suspensions, oil, fog, sublimation studies of air flow; or strobe lights and film cameras or high-speed digital cameras visualization).
...
Clearly, of all the tests performed up to date, NASA's tests have been the ones where most technical details have been disclosed. And NASA's tests in partial vacuum eliminate the effect of thermal convection through the air.
And while this may be a bit too much to expect from initial experiments, at least some basic level of critical thinking would be very welcome.
...Looking at Iulian Berca's tests. Very impressive at first sight. The weight is changing perfectly in sync with turning power on and off. So... this implies to suggest the effect is not thermal, and hence it should be the magic thrust. Ok, now turn it upside down. Wouldn't the magic thrust be expected to stay the same? Yet, the weight change is now only like 10% compared to the original configuration. Hence, a very sizable component of his initial observed force must be either thermal or Lorentz. Now... what in the world makes one believe that this thermal/Lorentz component is somehow less than the entire 100% of his observation?? Just because it changes in value between the 2 orientations??
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#1682 by dustinthewind on 13 Jan, 2016 22:01
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For example, the effect of natural thermal air convection from the fustrum with vortex shedding and Navier Stokes equation in a low Reynolds number regime above Stokes flow cannot be understood by experimenters, there has not been any Computational Fluid Dynamics of it, or visual study of it in slow motion, or experimental profiling of the air convection (no smoke, tufts, evaporating suspensions, oil, fog, sublimation studies of air flow; or strobe lights and film cameras or high-speed digital cameras visualization).
...
Clearly, of all the tests performed up to date, NASA's tests have been the ones where most technical details have been disclosed. And NASA's tests in partial vacuum eliminate the effect of thermal convection through the air.
And while this may be a bit too much to expect from initial experiments, at least some basic level of critical thinking would be very welcome.
...Looking at Iulian Berca's tests. Very impressive at first sight. The weight is changing perfectly in sync with turning power on and off. So... this implies to suggest the effect is not thermal, and hence it should be the magic thrust. Ok, now turn it upside down. Wouldn't the magic thrust be expected to stay the same? Yet, the weight change is now only like 10% compared to the original configuration. Hence, a very sizable component of his initial observed force must be either thermal or Lorentz. Now... what in the world makes one believe that this thermal/Lorentz component is somehow less than the entire 100% of his observation?? Just because it changes in value between the 2 orientations??
Another thought that comes to mind, is very hypothetical but, lets just suppose the EM drive were to push on a super-fluid quantum vacuum that was in motion with respect to it. Lets say the vacuum was accelerating into the earth. (later decelerating inside the earth as it moves towards the center till it reaches zero velocity to give zero gravity. Matter being some sort of vortex for super-fluid space time. Maybe giving the electron some intrinsic spin?) (Time passing by more slowly, closer to the surface of the earth being due to the difference in relative velocity with respect to the motion of the local quantum vacuum. Frame dragging being a similar phenomena but with a dtheta/dt angular velocity.) Is it possible that we might expect less thrust up than down with respect to pushing on a moving vacuum?
I am not dismissing the other factors you mentioned such as Lorentz and thermal. -
#1683 by ThinkerX on 14 Jan, 2016 02:43
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Doctor Rodal-Quote
In other words, for increasing dimensions of the cavity, preserving all geometrical ratios, and keeping material properties constant and for the same mode shape, the quality of resonance (Q) will increase with the square root of the dimension, also the skin depth will increase with the square root of the dimension, while the frequency will decrease, as the inverse of the dimension.
I am trying to wrap my mind around this statement, and am seeking clarity.
Given the above, were you to take the Eagleworks frustum, make it ten times the current size, and compensate for the frequency shift, then the same amount of power input would result in substantially stronger 'thrust.' Or did I misread that somehow? -
#1684 by Rodal on 14 Jan, 2016 02:53
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Doctor Rodal-
QuoteIn other words, for increasing dimensions of the cavity, preserving all geometrical ratios, and keeping material properties constant and for the same mode shape, the quality of resonance (Q) will increase with the square root of the dimension, also the skin depth will increase with the square root of the dimension, while the frequency will decrease, as the inverse of the dimension.
I am trying to wrap my mind around this statement, and am seeking clarity.
Given the above, were you to take the Eagleworks frustum, make it ten times the current size, and compensate for the frequency shift, then the same amount of power input would result in substantially stronger 'thrust.' Or did I misread that somehow?
Make any frustum of a cone (e.g. NASA's or Shawyer's Demonstrator or Yang's or Shell's) 10 times bigger diameters (both) and 10 times longer length, and use the same materials (copper for example), medium (air or vacuum), and excite the same mode shape
then:
* the Quality of resonance will be √10 = 3.16 times larger
* the force/PowerInput will be √10 = 3.16 times larger (according to all three theories: McCulloch, Shawyer and Notsosureofit), because Q will be √10 = 3.16 times larger
* the skin depth will be √10 = 3.16 times larger (*)
* the frequency will be 10 smaller, for the same mode shape
________
(*) obviously, frustums of a cone will have to accommodate this greater thickness,
Example:
Shawyer Demonstrator
L =0.2 m
Db = 0.28 m
Ds = 0.14921 m
Force/PowerInput = 243 (mN/kW)
Q = 45,000
frequency= 2.45 GHz
skin depth = 1.3171 micrometers (for copper)
____________________________________
10 times bigger
L =2 m
Db = 2.8 m
Ds = 1.4921 m
Force/PowerInput = 768 (mN/kW)
Q = 142,302
natural frequency= 0.245 GHz (@ same mode shape)
skin depth = 4.165 micrometers (for copper)
____________________________________
10 times smaller
L =0.02 m
Db = 0.028 m
Ds = 0.014921 m
Force/PowerInput = 77 (mN/kW)
Q = 14,230
natural frequency= 24.5 GHz (@ same mode shape)
skin depth = 0.4165 micrometers (for copper)
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#1685 by SteveD on 14 Jan, 2016 03:09
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For example, the effect of natural thermal air convection from the fustrum with vortex shedding and Navier Stokes equation in a low Reynolds number regime above Stokes flow cannot be understood by experimenters, there has not been any Computational Fluid Dynamics of it, or visual study of it in slow motion, or experimental profiling of the air convection (no smoke, tufts, evaporating suspensions, oil, fog, sublimation studies of air flow; or strobe lights and film cameras or high-speed digital cameras visualization).
...
Clearly, of all the tests performed up to date, NASA's tests have been the ones where most technical details have been disclosed. And NASA's tests in partial vacuum eliminate the effect of thermal convection through the air.
And while this may be a bit too much to expect from initial experiments, at least some basic level of critical thinking would be very welcome.
...Looking at Iulian Berca's tests. Very impressive at first sight. The weight is changing perfectly in sync with turning power on and off. So... this implies to suggest the effect is not thermal, and hence it should be the magic thrust. Ok, now turn it upside down. Wouldn't the magic thrust be expected to stay the same? Yet, the weight change is now only like 10% compared to the original configuration. Hence, a very sizable component of his initial observed force must be either thermal or Lorentz. Now... what in the world makes one believe that this thermal/Lorentz component is somehow less than the entire 100% of his observation?? Just because it changes in value between the 2 orientations??
Bad argument. Thermal lift is in the range of several grams. Berca got something stronger than lift downward, but not by much. -
#1686 by TheTraveller on 14 Jan, 2016 03:28
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Then we have this from Eagleworks suggesting thrust does not scale in a linear fashion:
http://nextbigfuture.com/2015/04/eagleworks-nasa-updated-emdrive-models.html
If the copper frustum was cooled by LN2 instead of H2O, the Q should increase ~3x and the thrust should increase from 2,000N to 6,000N.
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#1687 by SteveD on 14 Jan, 2016 03:29
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<rant on>
Armed with my first-hand experience about how easy it is to produce 500 uN of asymmetric “thrust” by just having a vertical metal plate dissipating 100W of heat, I decided to take another look at all the “positive” results listed for EmDrive… IMHO, we are going through some kind of mass delusion and wishful thinking effect here…
WIth these theoretical discussions, if you give some of the various theories charity, it is understandable that there might be a reversed force at some point, although I am not suggesting that's what you saw with your test set-up.
But why even start with all those amazing theories when a simple explanation is readily available (and nobody has done anything to prove the simple explanation wrong or even question it enough)?
Well in your case, primarily because you have a poorly made frustum without flat endplates being tested on a rig that is so noisy that the statistician through up his hands and said the data was unusable. It also doesn't help that your rig is hand made and we are not sure if that 500 uN of force is unique to your setup or not. Further, you've declared that the drive does not work after running it in a configuration predicted to produce no thrust. I expect people are listening when it comes to establishing how much force is needed to separate signal from noise. -
#1688 by Rodal on 14 Jan, 2016 03:51
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Then we have this from Eagleworks suggesting thrust does not scale in a linear fashion:
http://nextbigfuture.com/2015/04/eagleworks-nasa-updated-emdrive-models.html
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NASA's QV theory (according to March in previous threads) is not proportional to Q (unlike the theories of McCulloch, Shawyer and Notsosureofit) and hence it is not surprise that Force/PowerInput should not scale like Q either, for the QV theory. It is very dependent on mode shape.
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#1689 by ThinkerX on 14 Jan, 2016 04:05
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Quote
Make any frustum of a cone (e.g. NASA's or Shawyer's Demonstrator or Yang's or Shell's) 10 times bigger diameters (both) and 10 times longer length, and use the same materials (copper for example), medium (air or vacuum), and excite the same mode shape
then:
* the Quality of resonance will be √10 = 3.16 times larger
* the force/PowerInput will be √10 = 3.16 times larger (according to all three theories: McCulloch, Shawyer and Notsosureofit), because Q will be √10 = 3.16 times larger
* the skin depth will be √10 = 3.16 times larger (*)
* the frequency will be 10 smaller, for the same mode shape
I wonder...might this not account in part for the differences in the two sets of Vacuum tests? The Eagleworks Frustum was larger by far, and 'apparently' generated significant thrust, while the other frustum was smaller, hence with more borderline results. Of course other major factors were present with both sets of tests.
So, if significant thrust in a vacuum is the goal, then the test frustum should be as large as you can make it and still fit it into the vacuum chamber.
It also makes me wonder if somehow the concepts of Not-so-sure-of-it, McCulloch, and Shawyer are not so much 'theories,' but ''formula which sort of fit the observations.' Thinking here of Kepler, who correctly calculated orbital solutions, but missed out on a viable theory of gravity. It wasn't until Newton that the reason why Kepler's equations worked became apparent. -
#1690 by SteveD on 14 Jan, 2016 04:08
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These conundrums seem to point toward some form of relativistic explanation not considered in the classic equations.
First, you are dealing with photons, they are by definition relativistic, so you need to include relativity if you want things to add up.
Second, I do not recommend you try to think about relativity until you understand basic physics first. You keep using Watts (Power which is energy per time) and Joules (energy) interchangeably. The difference between them is the difference between a constantly running faucet and a bucket of water sitting on a table. I do not believe this is the right place for me to teach these concepts, and I recommend taking an actual class in physics to learn them.QuoteThe joule (/ˈdʒuːl/), symbol J, is a derived unit of energy in the International System of Units.[1] It is equal to the energy transferred (or work done) to an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre (1 newton metre or N·m). It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889).[2][3][4]
In terms firstly of base SI units and then in terms of other SI units:
. . .
One joule can also be defined as:
The work required to move an electric charge of one coulomb through an electrical potential difference of one volt, or one '"coulomb volt" (C·V). This relationship can be used to define the volt.
The work required to produce one watt of power for one second, or one "watt second" (W·s) (compare kilowatt hour - 3.6 megajoules). This relationship can be used to define the watt.
https://en.wikipedia.org/wiki/JouleQuoteThe watt (symbol: W) is a derived unit of power in the International System of Units (SI), named after the Scottish engineer James Watt (1736–1819). The unit is defined as joule per second[1] and can be used to express the rate of energy conversion or transfer with respect to time. It has dimensions of L2MT−3.
https://en.wikipedia.org/wiki/Watt
It would seem like, definitionally, Watt/seconds and Joules may be used interchangeably. Perhaps if I had specified that the acceleration takes place over one second to make the issue explicit?Quote
3. Again you confused J and W. Your calculation is simply wrong and I believe your claim of constant force per power would be false due to the redshift of the reflections when the mirrors are traveling at higher relative velocities.
I could take your examples 1 and 3, redefine them correctly and work through them, but I don't think that would be beneficial at this point. First you should get a better understanding of physics 101.
Perhaps it might be useful to work through these to see if anything odd is happening? -
#1691 by SteveD on 14 Jan, 2016 04:38
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.../...
This is more than I can take. Sorry.
Care to comment about https://forum.nasaspaceflight.com/index.php?topic=39004.msg1461319#msg1461319 where relative velocities are clearly stated and where there is no acceleration involved (i.e. no need to getting lost with KE deltas) ?
Is this what you're talking about?Quoteemdrive with "figure of merit" φ (in Newtons per electrical Watt)
Needed flow of power (from ground), Pnf=F/φ
Feedback loop power Pfl=ηFV
Whenever V>1/(ηφ) we have Pfl>F/φ
And so for such V>1/(ηφ) : Pfl>Pnf
Overall the system acts as a constant power output Pfl-Pnf>0 while remaining in a stationary situation.
With φ=.1 N/kW and η=.1 the overunity appear above 100km/s
With φ=1 N/kW and η=.5 the overunity appear above 2km/s, this is in the ballpark of energy storage flywheels tangential velocities...
Only a φ<3.33 µN/kW (photon rocket) can guarantee that such V>1/(ηφ) can never be exceeded (even with ideally rigid materials and asymptotically close to one efficiency) because that would make V>c
Conclusion, it is simply wrong to say that conventional proven propulsive schemes suffer from the same apparent conservation of energy issue as the propellantless schemes claiming above 3.33 µN/kW "figure of merit". Only propellantless schemes claiming above 3.33 µN/kW have this problem. It is "instantaneous", it appears on any (non 0) arbitrarily small delta time interval. At a minimum, such propellantless schemes shouldn't be longer qualified as drives, but rather as sails or generators, i.e. systems which are known to exhibit net power output production while remaining in a stationary situation (because fed by an "infinite" or huge enough reserve of energy).
To comment, please refer only to units of power(W), force(N), relative velocities(m/s), mass flow rates (kg/s), as nothing else is needed and those eschew the problems with arbitrary choices of reference frames.
What is your argument? It can't be that a photonic laser thruster can't work, there is some pretty clear evidence that it does: http://www.ykbcorp.com/downloads/Photonic-Laser-Thruster-Propels-Simulated-Spacecraft_MP_ykb_ejw05-12-15.pdf. Are you arguing that a PLT requiring two spacecraft or that the redshift involved makes it less than propellantless? The first seems questionable, the second might very well be the case. I can't help but feel that the relativistic equations might help give us some insight into what (if anything) is happening with an EMDrive.
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#1692 by RFPlumber on 14 Jan, 2016 04:53
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... what in the world makes one believe that this thermal/Lorentz component is somehow less than the entire 100% of his observation?? Just because it changes in value between the 2 orientations??
Bad argument. Thermal lift is in the range of several grams. Berca got something stronger than lift downward, but not by much.
This actually answers my rhetorical question above pretty well. What makes one believe is the assumption that buoyancy / thermal lift is somehow the only possible cause for any force, and if buoyancy is not the same between the 2 orientations then the only remaining rational explanation is magic thrust.
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#1693 by Notsosureofit on 14 Jan, 2016 11:47
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Quote
Make any frustum of a cone (e.g. NASA's or Shawyer's Demonstrator or Yang's or Shell's) 10 times bigger diameters (both) and 10 times longer length, and use the same materials (copper for example), medium (air or vacuum), and excite the same mode shape
then:
* the Quality of resonance will be √10 = 3.16 times larger
* the force/PowerInput will be √10 = 3.16 times larger (according to all three theories: McCulloch, Shawyer and Notsosureofit), because Q will be √10 = 3.16 times larger
* the skin depth will be √10 = 3.16 times larger (*)
* the frequency will be 10 smaller, for the same mode shape
I wonder...might this not account in part for the differences in the two sets of Vacuum tests? The Eagleworks Frustum was larger by far, and 'apparently' generated significant thrust, while the other frustum was smaller, hence with more borderline results. Of course other major factors were present with both sets of tests.
So, if significant thrust in a vacuum is the goal, then the test frustum should be as large as you can make it and still fit it into the vacuum chamber.
It also makes me wonder if somehow the concepts of Not-so-sure-of-it, McCulloch, and Shawyer are not so much 'theories,' but ''formula which sort of fit the observations.' Thinking here of Kepler, who correctly calculated orbital solutions, but missed out on a viable theory of gravity. It wasn't until Newton that the reason why Kepler's equations worked became apparent.
While I would have to agree with you on the other two, the hypothesis has only one assumption and no free variables. As a bonus for GR it has no explicit dependence on velocity.
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#1694 by RERT on 14 Jan, 2016 11:55
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I asked a while ago what the induced currents in the frustrum actually are. The COMSOL plot posted above reminded me of the question, and also gave a way to calculate an answer of sorts.
The plot shows parts of the frustrum radiating at 12 W/m^2.
Consider a sheet of copper 5mm thick and 1 metre on a side radiating at 12 W/m^2. Total power radiated is therefore 12W. The resistance of the slab is 3.4 x 10^-6 Ohms. The current is given by I^2*R = 12W, which I make 1.9*10^3 Amps per linear metre, and using V=IR gives V=0.65*10^-2 V/m. This calculation is obviously unsophisticated, but if anyone has better numbers, please feel free to advise.
At this level, say the hot 'ring' on the COMSOL plot was 5 cm wide, then the total current flow would be about 100 Amps.
A caveat is that I have no idea how much power was being pumped into the COMSOL simulation, but safe to say the current should scale with the square root of the power, at least at constant Q.
A couple of related thoughts:
1. Perhaps the effect (if it exists) has nothing to do with radiation pressure, but the arrangement contrives a way to put high frequency current loops in close proximity and specific phase to each other, cf the Tuval paper.
2. I'm sure someone will correct me if I'm wrong, but I believe that the resonant frustrum cavity solution publicised by Egan would have no currents in the walls. If that is the case, one wonders how that solution can be offered to prove there is no thrust, given how far from reality (or at least simulation!) it appears to be.
Regards,
R. -
#1695 by Rodal on 14 Jan, 2016 12:47
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I asked a while ago what the induced currents in the frustrum actually are. The COMSOL plot posted above reminded me of the question, and also gave a way to calculate an answer of sorts.
The plot shows parts of the frustrum radiating at 12 W/m^2.
Consider a sheet of copper 5mm thick and 1 metre on a side radiating at 12 W/m^2. Total power radiated is therefore 12W. The resistance of the slab is 3.4 x 10^-6 Ohms. The current is given by I^2*R = 12W, which I make 1.9*10^3 Amps per linear metre, and using V=IR gives V=0.65*10^-2 V/m. This calculation is obviously unsophisticated, but if anyone has better numbers, please feel free to advise.
At this level, say the hot 'ring' on the COMSOL plot was 5 cm wide, then the total current flow would be about 100 Amps.
A caveat is that I have no idea how much power was being pumped into the COMSOL simulation, but safe to say the current should scale with the square root of the power, at least at constant Q.
A couple of related thoughts:
1. Perhaps the effect (if it exists) has nothing to do with radiation pressure, but the arrangement contrives a way to put high frequency current loops in close proximity and specific phase to each other, cf the Tuval paper.
2. I'm sure someone will correct me if I'm wrong, but I believe that the resonant frustrum cavity solution publicised by Egan would have no currents in the walls. If that is the case, one wonders how that solution can be offered to prove there is no thrust, given how far from reality (or at least simulation!) it appears to be.
Regards,
R.
No.
1) As posted by RFPlumber, the images showQuoteCOMSOL surface power dissipation. Here's one I posted for TE012
. It is a transverse electric (TE) mode. Hence the electric field is parallel to the walls, never perpendicular to the walls. Hence the electric field does not result in any charges on the walls, and the electric field does not result in any currents on the walls
A tangential Electric Field will always be zero on a metal surface. This is because the free charge will swim around and cancel the hypothetical electric field out, simply by the attractive nature of charge.
2) The heating that you see is due to the magnetic field, it is due to induction heating, which produces small eddy currents. Eddy currents (also called Foucault currents) are loops of electric current induced within conductors by a changing magnetic field in the conductor, due to Faraday's law of induction. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field.
3) The COMSOL solution is similar to Greg Egan's solution, both solve the same equations: Maxwell equations, under the same assumptions. COMSOL solves Maxwell's equations numerically, using the Finite Element method. Greg Egan solves Maxwell's equations analytically, using spherical Bessel and associated Legendre functions. Same equations, similar solutions.
4) The hotter "ring" on the lateral conical walls, near the small end of the truncated cone, due to induction heating from the magnetic field, predicted by COMSOL is also predicted by Greg Egan:
The differences are due to the fact that Greg Egan example is for a truncated cone with half angle much larger than RFPlumber's, and much closer to the apex of the cone, hence significantly more different from a cylindrical cavity than in RFPlumber's example. Greg Egan's example is for a frustum of a cone with the small diameter way below the cut-off frequency for open waveguides. Of course as we learned in school, the cut-off frequency for open waveguides (advocated by Roger Shawyer) does not apply at all to a closed resonant cavity, and hence Greg Egan shows the cavity still able to resonate without a problem. However, the "hot ring" on the wall of Greg Egan's example is further distant from the small end because the example in Greg Egan is for resonance of a cavity bign much closer to the apex of the cone.
5) Like Greg Egan, I also use an exact solution to solve Maxwell's equations, in my case obtained using Wolfram Mathematica and my calculations always compare very closely to COMSOL's FEA solutions, as I have shown a number of times (including excellent comparison with Greg Egan), and you can verify here https://forum.nasaspaceflight.com/index.php?topic=39214.msg1469866#msg1469866 for comparison with NASA's results using COMSOL FEA, and versus NSF user X-Ray's solution using a completely different method.
Best regards,
JR -
#1696 by Rodal on 14 Jan, 2016 13:04
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Yes, the Notsosureofit hypothesis appears to be more sophisticated than the other two, in addition to the points raised above, the Notsosureofit hypothesis is the only one that explicitly takes into consideration the mode shapes.QuoteMake any frustum of a cone (e.g. NASA's or Shawyer's Demonstrator or Yang's or Shell's) 10 times bigger diameters (both) and 10 times longer length, and use the same materials (copper for example), medium (air or vacuum), and excite the same mode shape
then:
* the Quality of resonance will be √10 = 3.16 times larger
* the force/PowerInput will be √10 = 3.16 times larger (according to all three theories: McCulloch, Shawyer and Notsosureofit), because Q will be √10 = 3.16 times larger
* the skin depth will be √10 = 3.16 times larger (*)
* the frequency will be 10 smaller, for the same mode shape
I wonder...might this not account in part for the differences in the two sets of Vacuum tests? The Eagleworks Frustum was larger by far, and 'apparently' generated significant thrust, while the other frustum was smaller, hence with more borderline results. Of course other major factors were present with both sets of tests.
So, if significant thrust in a vacuum is the goal, then the test frustum should be as large as you can make it and still fit it into the vacuum chamber.
It also makes me wonder if somehow the concepts of Not-so-sure-of-it, McCulloch, and Shawyer are not so much 'theories,' but ''formula which sort of fit the observations.' Thinking here of Kepler, who correctly calculated orbital solutions, but missed out on a viable theory of gravity. It wasn't until Newton that the reason why Kepler's equations worked became apparent.
While I would have to agree with you on the other two, the hypothesis has only one assumption and no free variables. As a bonus for GR it has no explicit dependence on velocity.
Yet, how does the Notsosureofit hypothesis address the conservation of energy issues and frame-indifference, as best articulated by Frobnicat in these threads?
We need another poem to continue the last one, as the conservation of energy and frame-indifference counter-arguments persist
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#1697 by meberbs on 14 Jan, 2016 13:24
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It would seem like, definitionally, Watt/seconds and Joules may be used interchangeably. Perhaps if I had specified that the acceleration takes place over one second to make the issue explicit?
Watt * seconds is equivalent to Joules, not Watt/seconds. You need to be careful and say exactly what you mean, or you get nonsensical answers.Quote
3. Again you confused J and W. Your calculation is simply wrong and I believe your claim of constant force per power would be false due to the redshift of the reflections when the mirrors are traveling at higher relative velocities.
I could take your examples 1 and 3, redefine them correctly and work through them, but I don't think that would be beneficial at this point. First you should get a better understanding of physics 101.
Perhaps it might be useful to work through these to see if anything odd is happening?
If you show that you understand the basics enough by stating the scenarios in a manner that at least uses consistent units and preferably doesn't jump reference frames, I might consider it. I already know why those scenarios will not have the issues you described from experience working similar problems. Typing the details out here would take time I don't want to spend, and would not be particularly enlightening on the emDrive.
Also if you want to learn physics, going through the steps yourself would be more beneficial to you. If you want to work through it, start by being careful with your units, and then be sure to do all calculations from just one reference frame (this simplifies a lot of things), and remember that if the laser emitter is moving in the chosen frame, its output will be doppler shifted. -
#1698 by Notsosureofit on 14 Jan, 2016 13:27
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Yet, how does the Notsosureofit hypothesis address the conservation of energy issues and frame-indifference, as best articulated by Frobnicat in these threads?
We need another poem to continue the last one, as the conservation of energy and frame-indifference counter-arguments persist
Still slowly working on that.
The hypothesis, so far, treats only the static force on the cavity. I need to finish the dependence on acceleration next. (update soon) Then we can treat the above. Note that the conservation law in GR is NOT the same as in SR. -
#1699 by rfmwguy on 14 Jan, 2016 15:49
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@zellerium...hi Kurt, just wanted to verify that you added the emdrive.wiki data yourself
