General Discussion > New Physics for Space Technology
Resonant Cavity Space-Propulsion: institutional experiments and theory
Rodal:
EXPERIMENTAL PROOF THAT NASA'S TEST WITHOUT A DIELECTRIC INSERT WAS IN RESONANCE AT THE FREQUENCY REPORTED IN NASA'S REPORT
Since we had concluded in http://forum.nasaspaceflight.com/index.php?topic=39214.msg1470613#msg1470613
that:
--- Quote --- for NASA's experiment without a dielectric we can say that the exact solution says that there was indeed a natural frequency for mode TE012 within 0.1% of the measured frequency, but as to whether the measured frequency was at the resonant peak, one has to rely on NASA's team having actually found peak resonance with S21 and S11 measurements (because we don't know the dimensions of NASA's resonant cavity to the precision required to calculate the resonant peak with all the required digits of numerical precision).
--- End quote ---
Finally, we reproduce again the experimental data from NASA Johnson Eagleworks Laboratory that proves that their experiment without dielectric inserts in their frustum of a cone cavity was indeed in resonance.
The resonance for mode shape TE012 without dielectric inserts was measured with an Agilent Model 9923A, 4.0 GHz Field Fox Vector Network Analyzer (VNA) both in the S11 and S21 modes (as shown in the pictures below) using the frustum RF loop antenna as input and the frustum sense antenna located 180 degrees around from the loop antenna with both antennas being at the same 15% of the height from the large end of the frustum, i.e., 0.15 * 9.00” = 1.35” or 34.29mm away from the large end.
The TE012 resonant frequency without the dielectric PE disc inserts was measured at 2.167137 GHz using either the S11 or S21 methods as shown by the two attached VNA slides.
Thus, any claims made about this test without dielectric inserts in NASA's frustum of a cone cavity with mode shape TE012 at 2.167 GHz not being in resonance are shown to be completely baseless, false and misleading.
This, factual information shows without a doubt that indeed NASA's frustum of a cone without dielectric inserts was in resonance with mode shape TE012 at 2.167 GHz in agreement with NASA's report and in agreement with the COMSOL Finite Element Analysis calculation and in agreement with the exact solution I calculated using Wolfram Mathematica.
X_RaY:
--- Quote from: Rodal on 01/11/2016 07:28 pm ---EXPERIMENTAL PROOF THAT NASA'S TEST WITHOUT A DIELECTRIC INSERT WAS IN RESONANCE AT THE FREQUENCY REPORTED IN NASA'S REPORT
Since we had concluded in http://forum.nasaspaceflight.com/index.php?topic=39214.msg1470613#msg1470613
that:
--- Quote --- for NASA's experiment without a dielectric we can say that the exact solution says that there was indeed a natural frequency for mode TE012 within 0.1% of the measured frequency, but as to whether the measured frequency was at the resonant peak, one has to rely on NASA's team having actually found peak resonance with S21 and S11 measurements (because we don't know the dimensions of NASA's resonant cavity to the precision required to calculate the resonant peak with all the required digits of numerical precision).
--- End quote ---
Finally, we reproduce again the experimental data from NASA Johnson Eagleworks Laboratory that proves that their experiment without dielectric inserts in their frustum of a cone cavity was indeed in resonance.
The resonance for mode shape TE012 without dielectric inserts was measured with an Agilent Model 9923A, 4.0 GHz Field Fox Vector Network Analyzer (VNA) both in the S11 and S21 modes (as shown in the pictures below) using the frustum RF loop antenna as input and the frustum sense antenna located 180 degrees around from the loop antenna with both antennas being at the same 15% of the height from the large end of the frustum, i.e., 0.15 * 9.00” = 1.35” or 34.29mm away from the large end.
The TE012 resonant frequency without the dielectric PE disc inserts was measured at 2.167137 GHz using either the S11 or S21 methods as shown by the two attached VNA slides.
Thus, any claims made about this test without dielectric inserts in NASA's frustum of a cone cavity with mode shape TE012 at 2.167 GHz not being in resonance are shown to be completely baseless, false and misleading.
This, factual information shows without a doubt that indeed NASA's frustum of a cone without dielectric inserts was in resonance with mode shape TE012 at 2.167 GHz in agreement with NASA's report and in agreement with the COMSOL Finite Element Analysis calculation and in agreement with the exact solution I calculated using Wolfram Mathematica.
--- End quote ---
Based on this measurement data I've got a look to my calculated frequency for this case and find:
Mode calculated(GHz) Comsol(GHz) diff Comsol(%) diff Comsol(GHz) measured NASA(GHz) diff meas.(%)
TE012 2,1653438127 2,1794 -0,64 -0,014 2,167138 -0,08279
Maybe its based on tiny differences between the final real measured cavity and the Comsol simulation.
Of course there are much larger differences for many of the other modes in my spreadsheet*. As I wrote elsewhere
I believe more in field simulations because it works.
* I use it only for general overview.
Rodal:
--- Quote from: X_RaY on 01/11/2016 08:23 pm ---
--- Quote from: Rodal on 01/11/2016 07:28 pm ---EXPERIMENTAL PROOF THAT NASA'S TEST WITHOUT A DIELECTRIC INSERT WAS IN RESONANCE AT THE FREQUENCY REPORTED IN NASA'S REPORT
Since we had concluded in http://forum.nasaspaceflight.com/index.php?topic=39214.msg1470613#msg1470613
that:
--- Quote --- for NASA's experiment without a dielectric we can say that the exact solution says that there was indeed a natural frequency for mode TE012 within 0.1% of the measured frequency, but as to whether the measured frequency was at the resonant peak, one has to rely on NASA's team having actually found peak resonance with S21 and S11 measurements (because we don't know the dimensions of NASA's resonant cavity to the precision required to calculate the resonant peak with all the required digits of numerical precision).
--- End quote ---
Finally, we reproduce again the experimental data from NASA Johnson Eagleworks Laboratory that proves that their experiment without dielectric inserts in their frustum of a cone cavity was indeed in resonance.
The resonance for mode shape TE012 without dielectric inserts was measured with an Agilent Model 9923A, 4.0 GHz Field Fox Vector Network Analyzer (VNA) both in the S11 and S21 modes (as shown in the pictures below) using the frustum RF loop antenna as input and the frustum sense antenna located 180 degrees around from the loop antenna with both antennas being at the same 15% of the height from the large end of the frustum, i.e., 0.15 * 9.00” = 1.35” or 34.29mm away from the large end.
The TE012 resonant frequency without the dielectric PE disc inserts was measured at 2.167137 GHz using either the S11 or S21 methods as shown by the two attached VNA slides.
Thus, any claims made about this test without dielectric inserts in NASA's frustum of a cone cavity with mode shape TE012 at 2.167 GHz not being in resonance are shown to be completely baseless, false and misleading.
This, factual information shows without a doubt that indeed NASA's frustum of a cone without dielectric inserts was in resonance with mode shape TE012 at 2.167 GHz in agreement with NASA's report and in agreement with the COMSOL Finite Element Analysis calculation and in agreement with the exact solution I calculated using Wolfram Mathematica.
--- End quote ---
Based on this measurement data I've got a look to my calculated frequency for this case and find:
Mode calculated(GHz) Comsol(GHz) diff Comsol(%) diff Comsol(GHz) measured NASA(GHz) diff measured(%)
TE012 2,1653438127 2,1794 -0,64 -0,014 2,167138 -0,08279
Maybe its based on tiny differences between the final real measured cavity and the Comsol simulation.
Of course there are much larger differences for many of the other modes in my spreadsheet*. As I wrote elsewhere I believe more in field simulations because it works.
* I use it only for general overview.
--- End quote ---
Excellent, your solution gives the same natural frequency (2.165 GHz) I calculated with the exact solution using Wolfram Mathematica, as reported here: http://forum.nasaspaceflight.com/index.php?topic=39214.msg1469866#msg1469866
Further evidence that validates NASA's report that the test without dielectric insert was in TE012 mode shape resonance at the measured frequency !
I think that NASA built the truncated cone cavity to within measurement tolerances of +/-0.01” , giving internal dimensions as follows
bigDiameter = (11.00") +/-0.01” ---> total % error = 0.18% = 1/550
smallDiameter = (6.25") +/-0.01”--->total % error = 0.32% = 1/313
axialLength = (9") +/-0.01” ---> total % error = 0.22% = 1/450
Therefore (taking the median total % error = 0.22% = 1/450) the dimensional tolerance of NASA's frustum is such that it is only for a Q<450 that one can hope to be within the resonant bandwidth, given the uncertainty due to dimensions ( 1/450).
Importantly, the difference between both X-Ray's solution and the exact solution using Wolfram Mathematica from the measured frequency of -0.1% is well within the geometrical tolerance uncertainty of NASA's truncated cone itself. See NASA's design dimensions for their frustum of a cone, attached below
Rodal:
QUALITY OF RESONANCE "Q" FOR NASA'S TEST WITHOUT A DIELECTRIC INSERT
Finally, what was the predicted Quality of Resonance ("Q") for NASA's test without a dielectric insert?
Using the following resistivity for the copper alloy used for this test:
Material: Copper alloy 101
resistivity = 1.71*10^(-8) ohm meter
Sources for this material value:
http://www.azom.com/article.aspx?ArticleID=2850#_Physical_Properties_of http://www.husseycopper.com/production/alloys/electrical/c-101-00/
Using the following geometrical dimensions for the frustum of a cone, as used by Frank Davis:
bigDiameter = (11.01 inch)*(2.54 cm/inch)*(1 m/(100 cm));
smallDiameter = (6.25 inch)*(2.54 cm/inch)*(1 m/(100 cm));
axialLength = (9 inch)*(2.54 cm/inch)*(1 m/(100 cm));
the exact solution, using Wolfram Mathematica to solve Maxwell's equations, gives:
Q = 78642
So, a very good Q value is predicted for mode shape TE012 at the frequency:
measured frequency at which NASA test was performed: 2.168 GHz
calculated natural frequency (exact solution, Dr. Rodal using Wolfram Mathematica): 2.165 GHz
for NASA's test without a dielectric insert that resulted in no thrust.
The fact that this NASA test resulted in zero "anomalous force", and that Paul March at NASA had the great insight to introduce dielectric inserts at the small end to produce the anomalous force, is one of the most important data point in the history of EM Drive experiments
X_RaY:
--- Quote from: Rodal on 01/12/2016 07:43 pm ---QUALITY OF RESONANCE "Q" FOR NASA'S TEST WITHOUT A DIELECTRIC INSERT
Finally, what was the predicted Quality of Resonance ("Q") for NASA's test without a dielectric insert?
Using the following resistivity for the copper alloy used for this test:
Material: Copper alloy 101
resistivity = 1.71*10^(-8) ohm meter
Sources for this material value:
http://www.azom.com/article.aspx?ArticleID=2850#_Physical_Properties_of http://www.husseycopper.com/production/alloys/electrical/c-101-00/
Using the following geometrical dimensions for the frustum of a cone, as used by Frank Davis:
bigDiameter = (11.01 inch)*(2.54 cm/inch)*(1 m/(100 cm));
smallDiameter = (6.25 inch)*(2.54 cm/inch)*(1 m/(100 cm));
axialLength = (9 inch)*(2.54 cm/inch)*(1 m/(100 cm));
the exact solution, using Wolfram Mathematica to solve Maxwell's equations, gives:
Q = 78642
So, a very good Q value is predicted for mode shape TE012 at the frequency:
measured frequency at which NASA test was performed: 2.168 GHz
calculated natural frequency (exact solution, Dr. Rodal using Wolfram Mathematica): 2.165 GHz
for NASA's test without a dielectric insert that resulted in no thrust.
The fact that this NASA test resulted in zero "anomalous force", and that Paul March at NASA had the great insight to introduce dielectric inserts at the small end to produce the anomalous force, is one of the most important data point in the history of EM Drive experiments
--- End quote ---
These are great news. :) I came to nearly the same conclusion some time last year(Q=79011). I never post it, at least I am not sure about the formula (found an approximation in an cern paper about cavities if my memory is correct) and my implementation. No -3dB bandwidth needed for the calculation, its mode,volume, conductivity dependent.
Based on this the Q at larger volumes is in general (mode dependent) bigger than for smaller volume. I think more energy can be stored in larger volumes.
If I try to use to divide all dimensions by a factor of 10, I get a 10 times higher resonant frequency (good so far) but a Q of only 24985. Could you so kind to check this please, I can feel something may still wrong with this calculation although the number for the original dimensions fits yours very well.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version