FYIRoughly 8 X 10^8 Nm/kg is the minimum needed from Earth orbit to Pluto's ..Just passing thru so maybe not relevant ?
EM DRIVE FORCE vs. TIME The stress component σxx is compressive at both bases. Therefore the force obviously points in different directions: at the big base it points in the direction from the small base to the big base while at the small base it points in the direction from the big base to the small base. From the interior to the surface in both cases.
Quote from: Notsosureofit on 07/18/2015 03:06 pmFYIRoughly 8 X 10^8 Nm/kg is the minimum needed from Earth orbit to Pluto's ..Just passing thru so maybe not relevant ?Which amounts to a deltaV of 40km/s, the claimed short transit time (unadulterated 1N/kW => 12.4 month) amounts to deltaV of 360km/s, square the ratio for energy density comparison... at those levels trajectories becomes quite straight and Sun's gravity well (departure from LEO) becomes a marginal gentle slope.
Quote from: rfmwguy on 07/18/2015 02:14 pmProper scientific study is small steps with valid results. Hyperbole like heavy lifters, mass production and pluto missions are, well...hypobole. Yes, I am a sales and marketing expert with a very technical background. I would humbly suggest we leave sales & marketing/blue sky plans to another forum. Not that we can't deam, however...The big difference between Internet Forums and sales and marketing in the real commercial world is that in an Internet Forum sales and marketing hyperbole can be done posting anonymously in various forums, so when the dreams of honest followers and believers that have invested their time in such hopes are eventually dashed, there will be no loss of reputation of the anonymous poster, who can then quietly disappear and assume another moniker.In the stock market it is well known that financial message boards are full of anonymous posters that use financial message board forums to "pump and dump" stocks playing on the hope and fear of honest stock market investors: https://en.wikipedia.org/wiki/Pump_and_dump
Proper scientific study is small steps with valid results. Hyperbole like heavy lifters, mass production and pluto missions are, well...hypobole. Yes, I am a sales and marketing expert with a very technical background. I would humbly suggest we leave sales & marketing/blue sky plans to another forum. Not that we can't deam, however...
Quote from: rq3 on 07/18/2015 02:12 pmQuote from: TheTraveller on 07/18/2015 02:58 amQuote from: Rodal on 07/18/2015 02:47 amQuote from: TheTraveller on 07/18/2015 02:42 amQuote from: Rodal on 07/18/2015 02:35 amSeeShells: notice<< to my specs ....and N2 filled >> chirality and nitrongen inversion at room temperaturePure N2 in my cavity can convert to chiral molecules??Are you using polymer O Rings ?Was planning on using space qualified (no outgassing) silicon O rings.I've never heard of a silicon "O" ring. If there is such an animal, it would be fantastically brittle. If you actually mean "silicone", they may be low outgassing and "space qualified" but will be VERY gas permeable. Perhaps almost as bad as polytetrafluoroethylene.You might want to contact a company like Chomerics, who specializes in conductive "O" rings for applications like this. Good luck.So quick to attach! Apologies, dropped the e. Sometime my big fingers on a small mobile phone screen gens typos or my old eyes miss errors.Will probably be a gasket. Have a few mates in the aerospace industry that are working on the best material to provide good electrical conductivity and good sealing, with min outgassing using N2 inside the frustum at 1/2 atmo pressure.You have any suggestions?
Quote from: TheTraveller on 07/18/2015 02:58 amQuote from: Rodal on 07/18/2015 02:47 amQuote from: TheTraveller on 07/18/2015 02:42 amQuote from: Rodal on 07/18/2015 02:35 amSeeShells: notice<< to my specs ....and N2 filled >> chirality and nitrongen inversion at room temperaturePure N2 in my cavity can convert to chiral molecules??Are you using polymer O Rings ?Was planning on using space qualified (no outgassing) silicon O rings.I've never heard of a silicon "O" ring. If there is such an animal, it would be fantastically brittle. If you actually mean "silicone", they may be low outgassing and "space qualified" but will be VERY gas permeable. Perhaps almost as bad as polytetrafluoroethylene.You might want to contact a company like Chomerics, who specializes in conductive "O" rings for applications like this. Good luck.
Quote from: Rodal on 07/18/2015 02:47 amQuote from: TheTraveller on 07/18/2015 02:42 amQuote from: Rodal on 07/18/2015 02:35 amSeeShells: notice<< to my specs ....and N2 filled >> chirality and nitrongen inversion at room temperaturePure N2 in my cavity can convert to chiral molecules??Are you using polymer O Rings ?Was planning on using space qualified (no outgassing) silicon O rings.
Quote from: TheTraveller on 07/18/2015 02:42 amQuote from: Rodal on 07/18/2015 02:35 amSeeShells: notice<< to my specs ....and N2 filled >> chirality and nitrongen inversion at room temperaturePure N2 in my cavity can convert to chiral molecules??Are you using polymer O Rings ?
Quote from: Rodal on 07/18/2015 02:35 amSeeShells: notice<< to my specs ....and N2 filled >> chirality and nitrongen inversion at room temperaturePure N2 in my cavity can convert to chiral molecules??
SeeShells: notice<< to my specs ....and N2 filled >> chirality and nitrongen inversion at room temperature
https://en.m.wikipedia.org/wiki/Maxwell_stress_tensorQuote from: Rodal on 07/18/2015 01:09 amEM DRIVE FORCE vs. TIME The stress component σxx is compressive at both bases. Therefore the force obviously points in different directions: at the big base it points in the direction from the small base to the big base while at the small base it points in the direction from the big base to the small base. From the interior to the surface in both cases. I think Is the opposite Rodal.See in wikipedia, the force density f=div(sigma) +Poynting vector term, and the expressions "negative pressure" & "negative direction"If one want to calculate the force on a object ( the big end for example), one must enclose the object by a surface of outward normal orientation ,to use gauss divergence theorem, and to obtains a surface integral.For the big end, the normal of the enclosing surface, where the sigmas are non zero ( inside cavity), is pointing to -x direction, so when integrating the force on the big end , we have dfx=sigmaxx.(-ds).Then the force acting on big end is positive and pointing to positive x direction, because sigmaxx is negative.For the small end is the inverse.This is natural. The big end and the small and are both reflecting the waves backward to cavity.
Hello,I've been tinkering around with meep on Debian, and I have a procedure for installing meep 1.3 on Debian 8, which packages the older meep 1.2 by default:# apt-get install h5utils openmpi-bin# apt-get build-dep meep-openmpiThis installs everything we'll need for dependencies, but by default ./configure won't find libhdf5, so we need to do this.# cd /usr/lib/x86_64-linux-gnu/# ln -s libhdf5_openmpi.so libhdf5.so# export CPPFLAGS="-I/usr/include/hdf5/openmpi"Now we can head back to our source-building directory and get on with it.# wget http://ab-initio.mit.edu/meep/meep-1.3.tar.gz# cd meep-1.3# ./configure --with-mpi --prefix=$HOMEObviously this assumes $HOME is in your path, you can install it wherever.# make# make installIf anyone has meep files that they lack the time to process on their own hardware, I have a reasonably powerful system that can crank through a 12-thread run of NSF-1701.ctl in about 40 minutes, as well as a web server (nginx) running so I can package the output files (h5, csv, png, whatever) and provide a link. I'm a sysadmin by trade, and the last physics I took was Newton, so I don't yet know enough to write my own Scheme scripts for meep and get any meaningful output.Yes, for those wondering, I'm also tidux on /r/emdrive.
Quote from: frobnicat on 07/18/2015 03:26 pmQuote from: Notsosureofit on 07/18/2015 03:06 pmFYIRoughly 8 X 10^8 Nm/kg is the minimum needed from Earth orbit to Pluto's ..Just passing thru so maybe not relevant ?Which amounts to a deltaV of 40km/s, the claimed short transit time (unadulterated 1N/kW => 12.4 month) amounts to deltaV of 360km/s, square the ratio for energy density comparison... at those levels trajectories becomes quite straight and Sun's gravity well (departure from LEO) becomes a marginal gentle slope.The rocket equation and delta-v do not apply in this situation. There is no propellent being expelled. This is simple kinematics.x=1/2*a*t2, solve for time.Calculate for half the distance to account for acceleration and double the time to account for deceleration.A drive that produces 1 N for every 1000 W pumped into it is not a perpetual motion machine. It's not even efficient. The advantage is not having to carry and spew propellent out the back.Whether or not this is real or science fiction is the question.
I find it laughable to even talk about spaceships and missions without even having an established and widely accepted, repeatable science behind it. It baffles me to read time and again that Mr. Shawyer is sitting on the holy grail of propulsion, but doesn't seem to be willing to publicly present a current device that produces Newtons of thrust, as claimed by him since quite a long time now.Show it, or shut it.@RodalGreat work so far, good doctor
I have nothing against Roger Shawyer, the man. It seems he came across this phenomenon, tried to refine, explain and commercialize it, and for whatever reasons financial or intellectual has been unable to do so effectively. Where I take issue, however, is in the disconnect between his claims and his actions. He claims to hold in his hands the power to change and improve the world - to fundamentally alter the human experience for the better - and yet he seems to feel no moral imperative to do so. If it was me, I would shout from every mountaintop until the world heard. Including this one here, full of interested and capable theorists, experimentalists and supporters. I find it telling that this isn't happening.
Quote from: RonM on 07/18/2015 04:29 pmQuote from: frobnicat on 07/18/2015 03:26 pmQuote from: Notsosureofit on 07/18/2015 03:06 pmFYIRoughly 8 X 10^8 Nm/kg is the minimum needed from Earth orbit to Pluto's ..Just passing thru so maybe not relevant ?Which amounts to a deltaV of 40km/s, the claimed short transit time (unadulterated 1N/kW => 12.4 month) amounts to deltaV of 360km/s, square the ratio for energy density comparison... at those levels trajectories becomes quite straight and Sun's gravity well (departure from LEO) becomes a marginal gentle slope.The rocket equation and delta-v do not apply in this situation. There is no propellent being expelled. This is simple kinematics.x=1/2*a*t2, solve for time.Calculate for half the distance to account for acceleration and double the time to account for deceleration.A drive that produces 1 N for every 1000 W pumped into it is not a perpetual motion machine. It's not even efficient. The advantage is not having to carry and spew propellent out the back.Whether or not this is real or science fiction is the question.I'm sorry, but this is not even wrong. Do a simple calculation of energy in vs. energy out over time and you'll see the problem. What you mean by "is not efficient" is unclear.
Quote from: deltaMass on 07/18/2015 04:45 pmQuote from: RonM on 07/18/2015 04:29 pmQuote from: frobnicat on 07/18/2015 03:26 pmQuote from: Notsosureofit on 07/18/2015 03:06 pmFYIRoughly 8 X 10^8 Nm/kg is the minimum needed from Earth orbit to Pluto's ..Just passing thru so maybe not relevant ?Which amounts to a deltaV of 40km/s, the claimed short transit time (unadulterated 1N/kW => 12.4 month) amounts to deltaV of 360km/s, square the ratio for energy density comparison... at those levels trajectories becomes quite straight and Sun's gravity well (departure from LEO) becomes a marginal gentle slope.The rocket equation and delta-v do not apply in this situation. There is no propellent being expelled. This is simple kinematics.x=1/2*a*t2, solve for time.Calculate for half the distance to account for acceleration and double the time to account for deceleration.A drive that produces 1 N for every 1000 W pumped into it is not a perpetual motion machine. It's not even efficient. The advantage is not having to carry and spew propellent out the back.Whether or not this is real or science fiction is the question.I'm sorry, but this is not even wrong. Do a simple calculation of energy in vs. energy out over time and you'll see the problem. What you mean by "is not efficient" is unclear.Oh, I see what you mean. That is about 180 times too high. The upper theoretical limit would be about 0.0056N/kW. An actual drive would not be that good. This puts the EM drive at about an order of magnitude less thrust than ion propulsion.
Dr. Rodal - Looking at your net force curves and trying to see a graphic straight line average, it looks to me like the average force for that cycle is ~ -0.00045x10-12 N and changing (going more negative) at a rate of about 0.0002 x 10-12 N/cycle. Plug in period in seconds for cycle and you see that that is not to shabby. Well, maybe not great at about -0.5 micro-Newton/second. We need to see a larger number of cycles, either all together or intermittently from a longer simulation run, But You Need to Request Such a Run, clearly and unambiguously. If you would like to ask it of me, I will interface for you to make sure that someone running my model understands your request.
Quote from: Ricvil on 07/18/2015 03:38 pmhttps://en.m.wikipedia.org/wiki/Maxwell_stress_tensorQuote from: Rodal on 07/18/2015 01:09 amEM DRIVE FORCE vs. TIME The stress component σxx is compressive at both bases. Therefore the force obviously points in different directions: at the big base it points in the direction from the small base to the big base while at the small base it points in the direction from the big base to the small base. From the interior to the surface in both cases. I think Is the opposite Rodal.See in wikipedia, the force density f=div(sigma) +Poynting vector term, and the expressions "negative pressure" & "negative direction"If one want to calculate the force on a object ( the big end for example), one must enclose the object by a surface of outward normal orientation ,to use gauss divergence theorem, and to obtains a surface integral.For the big end, the normal of the enclosing surface, where the sigmas are non zero ( inside cavity), is pointing to -x direction, so when integrating the force on the big end , we have dfx=sigmaxx.(-ds).Then the force acting on big end is positive and pointing to positive x direction, because sigmaxx is negative.For the small end is the inverse.This is natural. The big end and the small and are both reflecting the waves backward to cavity.For a second order tensor, one defines the unit cube as follows:Stress component sign conventions are as follows.• For a normal stress: positive (negative) if it produces tension (compression) in the material.• For a shear stress: positive if, when acting on the + face identified by the first index, it pointsin the + direction identified by the second index. Example: τxy is + if on the +x face it pointsin the +y directionIt is the same in Continuum Mechanics, comprising solid and fluid mechanics, electromagnetism and General Relativity.By definition, equilibrium is embedded in the definition of the stress tensor unit cube: hence its symmetry. For example: on one face of the unit cube above you have σ11. On the opposite side of the cube you have σ11 acting in the OPPOSITE direction. If one face σ11 is applying pressure on the surface, on the opposite side you hve σ11 applying pressure on the other surface. There is no need to refer to the equilibrium equations involving the flux (Poynting vector), divergence etc., to ascertain the meaning of the stress tensor components. When analyzing a solid body, or a fluid problem, if you are told that the normal component of stress is negative you know that means COMPRESSION.As in Continuum Mechanics, it is easy:a negative stress tensor diagonal component means a compressive pressure on the unit cube (inward presssure on the surface)a positive stress tensor diagonal component means a tension on the unit cube (outward tension on the surface)Hence a negative value of the stress tensor means that the unit cube is in compression.Both the big and small bases are in a state of compression normal to the surface.The direction of the force is a compressive pressure pushing against the surface.It is the same situation as a compressive force acting on a solid surface, or a fluid. Negative stress means forces pressing on the surface, NOT pulling on them. "This is natural" and well understood: the electromagnetic fields produce a pressure on the surfaces, certainly they are not pulling on the surfaces, they are applying pressure on them. Hence the direction of the forces were correctly defined.