And whatever makes you think that the Woodward Effect is "accepted physics"?
Meepers...here's a video that describes my antenna placement in NSF-1701:
Quote from: X_RaY on 07/21/2015 07:26 pmQuote from: Ricvil on 07/21/2015 02:16 pmAnother thougth.upon reflection light undergoes a 180 degree phase change on metal surfacesYes, and this situation is modeled by a traveling wave with reverse propagation and exactly 180 degrees of phase difference producing a destructive interference exactly at the mirror position.With two mirrors one has to satisfy the destructive interference at two points simultaneously, and this condition defines the possibles modes on "cavity".This is a example of superposition principle to model boundary conditions.
Quote from: Ricvil on 07/21/2015 02:16 pmAnother thougth.upon reflection light undergoes a 180 degree phase change on metal surfaces
Another thougth.
Quote from: DeWeave on 07/21/2015 03:54 am...Reading Woodwards description of transient mass fluctuation, makes it sound very similar to what is being discussed here. Is there a possibility that all of standing waves and power being pumped into the copper fulstrum is making it mimic one of Woodwards capacitors? Would provide a (relatively) clean way to try to tie the effect back into the realm of accepted physics. But again, I may just be oversimplifying it.My take on it, if it's for real, is that it behaves like an animation I saw on (the only?) youtube lecture by Woodward; a rocket with a spring and brick on back bouncing its way forward, sort of like a squid.Unlike the Woodward effect which relies on the charged capacitor having more inertia than an uncharged one, the "Shawyer Effect" I call a "Sagnac Ratchet"; the force in the forward, and impedance in the reverse directions are the result the frustrum's asymmetrical dispersion, group velocity, and sum/difference frequency filtering characteristics.Maybe Shawyer would have gotten a different response if he made it clear it was acting as a ratchet, so CoM wouldn't have been the issue.
...Reading Woodwards description of transient mass fluctuation, makes it sound very similar to what is being discussed here. Is there a possibility that all of standing waves and power being pumped into the copper fulstrum is making it mimic one of Woodwards capacitors? Would provide a (relatively) clean way to try to tie the effect back into the realm of accepted physics. But again, I may just be oversimplifying it.
1) I have confirmed that the fact that the stress is much higher at the small base than the big base for Yang Shell has nothing to do with the RF feed being on. It is due to the standing waves2) I don't understand at the moment how these forces are going to be balanced in the conical lateral walls. That's one of the reasons that I wrote my own code to examine this. I am going to examine what is happening with the stress at the conical walls.3) It seems to me that to balance the greater force at the small end, the stress at the conical walls has to be a suction instead of a pressure (in order to give an axial component to balance the forces) or else there has to be a huge shear force to balance the greater force at the small end4) I understand that Coulomb forces due to the Magnetic Field producing eddy currents can result in a suction force.5) Regardless of the nature of the suction/and/or/shear stress necessary to balance the forces at the ends. I propose that it may be very easy to disrupt these forces. It seems to me that it may be much easier to maintain pressure than suction, and to maintain pressure than shear. WARNING: not a well-formed idea follows:6) Perhaps the "ratcheting" effect of the EM Drive is all due to the momentary disruption of these boundary conditions. In other words: set-up an electromagnetic field whereby there is greater force at the small end than the force at the big end. If the pressure at the small end is much greater, this has to be counterbalanced by a suction and/or shear on the conical lateral walls. While it may be possible to have suction and/or/shear due to the Magnetic field and eddy -currents, it may be easy to disrupt them, hence the ratcheting effect. It would be like disrupting boundary conditions in a submarine propeller with cavitation or disrupting the no-slip boundary condition in a fluid-elastic viscous flow (in this last case, resulting in stick-slip at the boundary oscillating between plug flow and viscous flow).
1) I have confirmed that the fact that the stress is much higher at the small base than the big base for Yang Shell has nothing to do with the RF feed being on. It is due to the standing waves
Quote from: Rodal on 07/21/2015 08:07 pm1) I have confirmed that the fact that the stress is much higher at the small base than the big base for Yang Shell has nothing to do with the RF feed being on. It is due to the standing wavesHow do you get standing waves with no RF feed? Some kind of Casimir effect
Quote from: Ricvil on 07/21/2015 07:58 pmQuote from: X_RaY on 07/21/2015 07:26 pmQuote from: Ricvil on 07/21/2015 02:16 pmAnother thougth.upon reflection light undergoes a 180 degree phase change on metal surfacesYes, and this situation is modeled by a traveling wave with reverse propagation and exactly 180 degrees of phase difference producing a destructive interference exactly at the mirror position.With two mirrors one has to satisfy the destructive interference at two points simultaneously, and this condition defines the possibles modes on "cavity".This is a example of superposition principle to model boundary conditions.There isn't destructive interference at all (otherwise there isn't a propagating wave...). Into the direction of the small diameter there will be a gain in the field strength (see horn antennas)I think the difference between a resonator and a waveguide is: (pre sign of the field,see picture-example for TE011)please correct me if i am wrong
...What I want to see is some of the qualitative behavior surmised by some (Traveler I think?) where the wave dissipates into the big end, aliasing into the wall as dissipation (ultimately) into thermal energy, creating a kind of momentum sink. If I understand correctly - we would need to model the dissipative wall effects in meep explicitly in the boundary condition, as this isn't a "multi-physics" package as was pointed out. We'd have whatever surface currents exist in the walls creating a dissipation into heat based on material characteristics, certainly do-able.Do I have this right? Is it important in the presumed phenomenology?
Quote from: X_RaY on 07/21/2015 07:26 pmupon reflection light undergoes a 180 degree phase change on metal surfacesYes, and this situation is modeled by a traveling wave with reverse propagation and exactly 180 degrees of phase difference producing a destructive interference exactly at the mirror position.With two mirrors one has to satisfy the destructive interference at two points simultaneously, and this condition defines the possibles modes on "cavity".This is a example of superposition principle to model boundary conditions.
upon reflection light undergoes a 180 degree phase change on metal surfaces
Well, yes but when the antenna is on the axis of rotation and either a point source or axial in length, the frustum is rotationally symmetric. Meep also allows specification of mirror symmetry which reduces run time significantly but does not address the granularity issue.
Quote from: rq3 on 07/21/2015 09:31 pmQuote from: Rodal on 07/21/2015 08:07 pm1) I have confirmed that the fact that the stress is much higher at the small base than the big base for Yang Shell has nothing to do with the RF feed being on. It is due to the standing wavesHow do you get standing waves with no RF feed? Some kind of Casimir effect No. It is similar to what happens when you strike a bell, and it continues to resonate when you are not hitting it. It is just oscillation at a natural frequency. The higher the Q the longer it will continue to resonate. The only reason why it stops resonating has to do with damping: damping is inversely proportional to Q.
3) It seems to me that to balance the greater force at the small end, the stress at the conical walls has to be a suction instead of a pressure (in order to give an axial component to balance the forces) or else there has to be a huge shear force to balance the greater force at the small end
<snip>So why are folks relying on MEEP to model a physical process that, according to known physics, is impossible? MEEP is a model itself, and must have been designed to give reliable results according to known physics. Attempting to warp the model to fit unknown physics seems like a phenomenal waste of time, especially when no one can replicate the effect of the unknown physics on a reliable basis.Good science goes:1) I believe that x may be true (hypothesis)2) Based on what I know, if I do y I should see z, proving or disproving x for this reason (theory)3) Do 2 above, with controls (experiment)4) Modify 1 based on results of 3 (new hypothesis) With MEEP:1) I believe that x may be true (hypothesis)DO2) Based on what I THINK I know, run a computer simulation of x, with uncontrolled variables3) When I don't get the results I expect, modify the computer simulationLOOP Until someone has a reliable, physical, and functional Emdrive with a signal (at least 4 sigma, not asking for the moon here) above noise, MEEP is worthless. Sorry folks. For those building hardware, keep it up. For those doing MEEP, stand by for useful data to plug in to your model.
Quote from: Rodal on 07/21/2015 12:43 pmQuote from: mwvp on 07/21/2015 06:35 am...Maybe Shawyer would have gotten a different response if he made it clear it was acting as a ratchet, so CoM wouldn't have been the issue."asymmetrical dispersion, group velocity, and sum/difference frequency filtering characteristics"don't really get around the Conservation of Momentum issue in a frame-indifferent Universe.It isn't a matter of getting around CoM, it's a matter of how its conforming with it.Quote from: mwvp on 07/21/2015 06:35 am...Conservation of Momentum issues remain, and as often remarked by Frobnicat and deltaMass, even more disturbing issues related to conservation of energy are brought forth.Yes, I followed that exchange a few days back, and felt like a naive sucker for trusting the rocket-scientists at Eagleworks' figures - 4N/kW, 2 week mars trips, et. I haven't had the heart, patience or time to do the math myself, but I get specifying constant force/power can result in CoE violation. Shame on them.And I know EW is testing several devices with several different theories and they have a few theories of their own. But don't fling Eagleworks' 4N/kW rottting, dead, CoM-violating cat at Shawyer, because he does point out he believes his gadget looses power with acceleration and conforms with CoE and CoM. This adds to his credibility. Eagleworks credibility should be questioned for sighting such figures as they have without qualification.
Quote from: mwvp on 07/21/2015 06:35 am...Maybe Shawyer would have gotten a different response if he made it clear it was acting as a ratchet, so CoM wouldn't have been the issue."asymmetrical dispersion, group velocity, and sum/difference frequency filtering characteristics"don't really get around the Conservation of Momentum issue in a frame-indifferent Universe.
...Maybe Shawyer would have gotten a different response if he made it clear it was acting as a ratchet, so CoM wouldn't have been the issue.
...Conservation of Momentum issues remain, and as often remarked by Frobnicat and deltaMass, even more disturbing issues related to conservation of energy are brought forth.
What I want to see is some of the qualitative behavior surmised by some where the wave dissipates into the big end, aliasing into the wall as dissipation (ultimately) into thermal energy, creating a kind of momentum sink.
Quote from: notarget on 07/21/2015 07:56 pmWhat I want to see is some of the qualitative behavior surmised by some where the wave dissipates into the big end, aliasing into the wall as dissipation (ultimately) into thermal energy, creating a kind of momentum sink."Momentum Sink" I like it. If the frustum acts as a Momentum Sink, soaking ALL of the radiation's (microwaves') momentum up and converting it into momentum of the frustum, then we avoid the conservation of momentum issues, right?