Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1880890 times)

Offline graybeardsyseng

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After some digging I've finally settled on a antenna. It will be placed through the small endcap which will act as a ground plane as well. Nice helical pattern and about 8 db of gain. An axial-mode quadrifilar helical antenna putting out a circularly polarized field. I wrote the company asking if they wanted to donate one, haven't heard back yet and If I don't I'll just make one.
http://orbanmicrowave.com/thebasicsofquadrifilarantennas/

Quadriflar antennas are great - excellent pattern and gain.   I have built several in the 430 Mhz and 900 Mhz range, very straightforward construction.    I'm sure you have the factors for calculating the dimensions but in case others might be interested here is a handy "calculator" for these antenna.

http://jcoppens.com/ant/qfh/calc.en.php

Herman
EMdrive - finally - microwaves are good for something other than heating ramen noodles and leftover pizza ;-)

Offline deuteragenie

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

It sure would help though if I had the BASH shell command file with which to make the runs. I know that someone or several people reading this knows how to use BASH to make it so. My problem is of course, like almost all software problems, that I need it now. And if I get multiple responses, that won't bother me a bit. Thank all in advance.

Also add your Meep run, generation of a few PNGs and upload of all files to the script.  Make your life easy, drink a beer while the machine works !

Offline Rodal

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

here it is !!!!!!!!!!!!
Oh. My. God.

The fractal views were due to very low numbers (10^-13) showing the fractality and randomness inherent in the Finite Difference numerical scheme, not in the physical problem.

The numbers now are much larger (2*10^-5 instead of 10^-13) and they show much better patterns
« Last Edit: 07/01/2015 06:49 PM by Rodal »

Offline SeeShells

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

here it is !!!!!!!!!!!!
Oh. My. God.

The fractal views were due to very low numbers (10^-13) showing the fractality and randomness inherent in the Finite Difference numerical scheme, not in the physical problem.

The numbers now are much larger and they show much better patterns
They do show better pictures and sorry to get so excited but they are very nice, got my pea brain a working in overtime.
shell

Offline aero

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This is a very old fix (2007) for that problem on windows.

Quoting from Meep-Discuss

I received some help from a collegue which proposed editing both selected
Makefile's and configure files: the lines
   LIBS=-lhdf5
Were replaced with
   LIBS=-lhdf5 -lm -lz -lsz
End Quote.

I believe that is also a current problem with the Python interface version of Meep and the latest upgrade. Not sure, my memory isn't what it used to be.

As for the Video, I did make the .png files, but all credit for making the video belongs to Tom Ligon, of Polywell fame.
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Offline SeeShells

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After some digging I've finally settled on a antenna. It will be placed through the small endcap which will act as a ground plane as well. Nice helical pattern and about 8 db of gain. An axial-mode quadrifilar helical antenna putting out a circularly polarized field. I wrote the company asking if they wanted to donate one, haven't heard back yet and If I don't I'll just make one.
http://orbanmicrowave.com/thebasicsofquadrifilarantennas/

Quadriflar antennas are great - excellent pattern and gain.   I have built several in the 430 Mhz and 900 Mhz range, very straightforward construction.    I'm sure you have the factors for calculating the dimensions but in case others might be interested here is a handy "calculator" for these antenna.

http://jcoppens.com/ant/qfh/calc.en.php

Herman
Thanks! I'll cross check my numbers. Thank goodness they are a forgiving design.

Offline VAXHeadroom

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As a means of comparison, this is an early movie (attached below with title "2.1-cone-out2.1" as a mp4 attachment - do NOT confuse with the YouTube movie shown as reference) that was posted by aero of NASA's EM Drive with a dielectric insert.  The Meep model in this movie is 2-D instead of 3-D.  Observe that it converges to a p=3 mode which was not observed in NASA' experiments (they only observed TM212 and TE012 both of which have p=2 insted of p=3).

The interesting thing that I would like to point out is that this movie shows:

1) The fields settle into standing waves, with a sinusoidal--in-time variation.  The behavior is as predicted by standard resonance in a cavity with standing waves fixed in space, instead of the always changing fluctuating steady state with time-asymmetry shown in the recent 3D modeling without a dielectric insert.

2) One can also clearly observe that although the EM Drive being modeled has flat ends, the wave field wants to settle into a spherical wave pattern in its interior, as it should be according to resonant standing waves.

So, it is clear that Meep can predict a standing wave field inside the EM Drive or a fluctuating, time-asymmetric field, depending on the Meep model.

Compare the attached movie mp4 movie using a 2-D model, to the behavior of Ex -y on this 3-D model on the YouTube here :

https://www.youtube.com/watch?t=26&v=Cm9Nl-x1hj4

Congratulations to Stephen: this is a very well done video.
After a quadrillion of dependency downloads and re-compiles, I am close to having the latest Meep source building completely on Linux... In fact it does build successfully already but is not able to locate the .h5 library, for unknown reasons.
Well... That's my video, so thank you :)  But I'm Emory Stagmer, not Stephen !
Emory Stagmer
  Executive Producer, Public Speaker UnTied Music - www.untiedmusic.com

Offline VAXHeadroom

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

here it is !!!!!!!!!!!!
Oh. My. God.
Exactly my response. That's an Alcubierre metric.  Sh!t just got real.
Emory Stagmer
  Executive Producer, Public Speaker UnTied Music - www.untiedmusic.com

Offline aero

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Thanks a lot!

Well ... That was easy (for me) and it ran just fine. Now all I need do is a mass edit to change the directory names and I've got it for the Perfect Metal cavity, too. (change the .sh file name, too)

Thanks again!

What happened to your post, though?
« Last Edit: 07/01/2015 07:14 PM by aero »
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Offline SeeShells

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

here it is !!!!!!!!!!!!
Oh. My. God.
Exactly my response. That's an Alcubierre metric.  Sh!t just got real.
I'm going to wait until the other views are uploaded to draw any serious conclusions but it sent cold chills up my arms.

Beautiful work, you guys rock!

Shell

Offline aero

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Quote
Well... That's my video, so thank you :)  But I'm Emory Stagmer, not Stephen !

That's not the same video that ran before, what happened. The one Dr. Rodal posted was my video, but the one you posted is your video?
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Offline tchernik

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

here it is !!!!!!!!!!!!
Oh. My. God.

The fractal views were due to very low numbers (10^-13) showing the fractality and randomness inherent in the Finite Difference numerical scheme, not in the physical problem.

The numbers now are much larger (2*10^-5 instead of 10^-13) and they show much better patterns

Interesting.

For the sake of those of us that aren't physicists. What are we seeing in that graph that looks quite like the Alcubierre metric?


Offline saucyjack

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I need to make 72 more runs of h5totxt and h5topng. Can someone help me by converting the attached list of commands into a BASH shell command file. Running those commands manually at the terminal is challenging, exhausting and very prone to errors and I haven't bothered to learn BASH since moving to Ubuntu from Windows a few months ago. Given one working command file, I can likely make the rest myself, and maybe learn to recognize a BASH command file in the process.

@aero- would this be of help?  PM me if it's not what you're looking for.  I don't have MEEP installed here but I think this should do the trick.

https://gist.github.com/rkaiser0324/551b6ce6f5b0bfe15286

Offline WarpTech

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

here it is !!!!!!!!!!!!
Oh. My. God.
Exactly my response. That's an Alcubierre metric.  Sh!t just got real.

No, it's just the difference between a peak and a tough in the E field, within circular boundary. Not quite the same thing... LOL!

Offline Rodal

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

here it is !!!!!!!!!!!!
Oh. My. God.

The fractal views were due to very low numbers (10^-13) showing the fractality and randomness inherent in the Finite Difference numerical scheme, not in the physical problem.

The numbers now are much larger (2*10^-5 instead of 10^-13) and they show much better patterns

Interesting.

For the sake of those of us that aren't physicists. What are we seeing in that graph that looks quite like the Alcubierre metric?
It does look like the distortion of space caused by an Alcubierre drive doesn't it?

But in this case we are looking at the magnitude of the electric field perpendicular to the base.

We are looking at the base of the truncated cone.  We are looking at the electric field with vector component perpendicular to the base of the wall.

This is a transverse magnetic mode, that has an electric field in the longitudinal direction of the EM Drive, perpendicular to the base.



 You see that the electric field is maximum (+ red , like a hill) at one side, minimum (- blue , like a deep valley) at the other side and zero at the middle line.  The height corresponds to the magnitude of the electric field.

The electric field fluctuates with time, so that what is a hill now will become a valley and what is a valley now will become a hill, fluctuating with a frequency of 2.45 * 10^9 times per second .
« Last Edit: 07/01/2015 08:14 PM by Rodal »

Offline wallofwolfstreet

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

here it is !!!!!!!!!!!!
Oh. My. God.
Exactly my response. That's an Alcubierre metric.  Sh!t just got real.

No, that really isn't an Alcubierre metric at all.  I'm sorry, but I feel almost obligated to nip this nonsense in the bud.

It looks somewhat like the 2D representation of the Alcubierre metric used to get the idea across in Dr. White's presentations.  That's all.  The Alcubierre metric is a solution to Einstein's field equations that results in a warping of 3 dimensional space such that there is an expansion of space behind an object (the "hill" in the 2D representation) and a contraction of space in front of an object (the "valley").  In the picture Rodal posted, we are just looking at EM fields imposed on the cavity walls, with height off the plane of the wall being used to indicate magnitude.  Any similarity to the Alcubierre metric (or rather the 2D approximation I should say) is purely coincidence. 

That exact same shape is produced as one of the mode shapes of a vibrating drum skin, or water sloshing in a bucket.  There is no connection. 

Offline SeeShells

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

here it is !!!!!!!!!!!!
Oh. My. God.

The fractal views were due to very low numbers (10^-13) showing the fractality and randomness inherent in the Finite Difference numerical scheme, not in the physical problem.

The numbers now are much larger (2*10^-5 instead of 10^-13) and they show much better patterns

Interesting.

For the sake of those of us that aren't physicists. What are we seeing in that graph that looks quite like the Alcubierre metric?
It does look like the distortion of space caused by an Alcubierre drive doesn't it?

But in this case we are looking at the magnitude of the electric field perpendicular to the base.

We are looking at the base of the truncated cone.  We are looking at the electric field with vector component perpendicular to the base of the wall.

This is a transverse magnetic mode, that has an electric field in the longitudinal direction of the EM Drive, perpendicular to the base.



 You see that the electric field is maximum (+ red , like a hill) at one side, minimum (- blue , like a deep valley) at the other side and zero at the middle line, and the electric field is practically linear in between.  The height corresponds to the magnitude of the electric field.

The electric field fluctuates with time, so that what is a hill now will become a valley and what is a valley now will become a hill, fluctuating with a frequency of 2.45 * 10^9 times per second .
Until I really looked at the name on the data set image you had me freaked out Doc. Shame on you. lol

All it is is one phase before shifting phase in the other direction. Too bad we couldn't somehow rotate the phase so it was always "insync"... back at ya Doc.

Shell

Offline aero

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Dr. Rodal and all.
The csv files are now up.

https://drive.google.com/folderview?id=0B1XizxEfB23tfmkxNm1Ha1YxR1NZU2ZjUUpBUVVGV0M4QUVxaGYySEVFam5jVzdRYy0tSWs&usp=sharing

Thanks to zxcvb who is brand new to NSF, the BASH command files ran like a charm. All 18 directions are included.

Now I need to edit them (a copy) to execute h5topng. That will take awhile but the images that are already up should be indicative. The difference is the 2.5 times increased resolution so the noise outside the cavity will be much lower for these cases.

Enjoy - and I expect questions as usual.
« Last Edit: 07/01/2015 07:53 PM by aero »
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Offline VAXHeadroom

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

here it is !!!!!!!!!!!!
Oh. My. God.
Exactly my response. That's an Alcubierre metric.  Sh!t just got real.

No, that really isn't an Alcubierre metric at all.  I'm sorry, but I feel almost obligated to nip this nonsense in the bud.

It looks somewhat like the 2D representation of the Alcubierre metric used to get the idea across in Dr. White's presentations.  That's all.  The Alcubierre metric is a solution to Einstein's field equations that results in a warping of 3 dimensional space such that there is an expansion of space behind an object (the "hill" in the 2D representation) and a contraction of space in front of an object (the "valley").  In the picture Rodal posted, we are just looking at EM fields imposed on the cavity walls, with height off the plane of the wall being used to indicate magnitude.  Any similarity to the Alcubierre metric (or rather the 2D approximation I should say) is purely coincidence. 

That exact same shape is produced as one of the mode shapes of a vibrating drum skin, or water sloshing in a bucket.  There is no connection.
OK, OK, I'll get less excited :)
Emory Stagmer
  Executive Producer, Public Speaker UnTied Music - www.untiedmusic.com

Offline wallofwolfstreet

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Yes, I plan to generate and upload the full set of 18 views and csv data files.

here it is !!!!!!!!!!!!
Oh. My. God.
Exactly my response. That's an Alcubierre metric.  Sh!t just got real.

No, that really isn't an Alcubierre metric at all.  I'm sorry, but I feel almost obligated to nip this nonsense in the bud.

It looks somewhat like the 2D representation of the Alcubierre metric used to get the idea across in Dr. White's presentations.  That's all.  The Alcubierre metric is a solution to Einstein's field equations that results in a warping of 3 dimensional space such that there is an expansion of space behind an object (the "hill" in the 2D representation) and a contraction of space in front of an object (the "valley").  In the picture Rodal posted, we are just looking at EM fields imposed on the cavity walls, with height off the plane of the wall being used to indicate magnitude.  Any similarity to the Alcubierre metric (or rather the 2D approximation I should say) is purely coincidence. 

That exact same shape is produced as one of the mode shapes of a vibrating drum skin, or water sloshing in a bucket.  There is no connection.
OK, OK, I'll get less excited :)

Sorry to be a kill joy, but knowing the way misinformation gets spread across the internet and not wanting to see anymore popsci articles on how "Nasa made a warp drive", I felt like I had to say something. 

This thread is fringe enough without having to needlessly bring warp ships into the fray ;)

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