Author Topic: Woodward's effect  (Read 802978 times)

Offline Monomorphic

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Re: Woodward's effect
« Reply #1200 on: 12/08/2017 12:43 pm »
The result is that the presence of air doesn't seem to change that much the signals magnitude and shape.

That is exactly what I meant.

Beside all the differences due to the different set up, I noticed that the "thrusts" signals you obtained (reply #1142, third figure) are all different both in magnitude and shape. I don't see the same level on consistency between the input and the output compared to those obtained by Woodward, Tajmar and Buldrini.

See image below. V3 of the shaker showed results very similar to woodward effect traces. I've not yet tried to make the traces look similar with V4. I suspect I will need to use chirps.
« Last Edit: 12/08/2017 12:44 pm by Monomorphic »

Offline Povel

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Re: Woodward's effect
« Reply #1201 on: 12/08/2017 02:53 pm »
Quote
That is exactly what I meant

Sorry, I didn't get it.

Quote
See image below. V3 of the shaker showed results very similar to woodward effect traces. I've not yet tried to make the traces look similar with V4. I suspect I will need to use chirps

They look similar in shape, but not in duration. Each one of those chirped pulses lasts for almost 10 seconds each, which might or might not be due to the calibration of the balance. In your case the frequency of the pulses seems to be much closer to the driving frequency of the shaker (like one would expect).

When I'm referring to the output obtained by Woodward and others I'm thinking about these traces down here. As you can see they are characterized by the presence of transients and by a quite steady signal in the middle.
While the magnitude of the thrust signal seems to vary in different tests, its main features don't.
The steady signal in the middle is what I find most interesting.

« Last Edit: 12/08/2017 02:55 pm by Povel »

Offline Monomorphic

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Re: Woodward's effect
« Reply #1202 on: 12/08/2017 04:36 pm »
They look similar in shape, but not in duration. Each one of those chirped pulses lasts for almost 10 seconds each, which might or might not be due to the calibration of the balance. In your case the frequency of the pulses seems to be much closer to the driving frequency of the shaker (like one would expect).

When I'm referring to the output obtained by Woodward and others I'm thinking about these traces down here. As you can see they are characterized by the presence of transients and by a quite steady signal in the middle.
While the magnitude of the thrust signal seems to vary in different tests, its main features don't.
The steady signal in the middle is what I find most interesting.

I definitely think I will need to use long duration chirps in order to obtain a more similar trace. As for the switching transients, those would be practically non-existent in the shaker because of the lower voltages and currents used. But I did notice ending transients on most of the runs above 30Hz.  Woodward would likely be pleased to see no transients as he has spent considerable effort trying to eliminate them.

Offline WarpTech

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Re: Woodward's effect
« Reply #1203 on: 12/08/2017 06:18 pm »
They look similar in shape, but not in duration. Each one of those chirped pulses lasts for almost 10 seconds each, which might or might not be due to the calibration of the balance. In your case the frequency of the pulses seems to be much closer to the driving frequency of the shaker (like one would expect).

When I'm referring to the output obtained by Woodward and others I'm thinking about these traces down here. As you can see they are characterized by the presence of transients and by a quite steady signal in the middle.
While the magnitude of the thrust signal seems to vary in different tests, its main features don't.
The steady signal in the middle is what I find most interesting.

I definitely think I will need to use long duration chirps in order to obtain a more similar trace. As for the switching transients, those would be practically non-existent in the shaker because of the lower voltages and currents used. But I did notice ending transients on most of the runs above 30Hz.  Woodward would likely be pleased to see no transients as he has spent considerable effort trying to eliminate them.

Chirping a magnetic solenoid probably won't work. From experience, I know that the hysteresis of a solenoid will cause it to "buzz" if there is not enough voltage for it to fully engage. Chirping the input signal I would expect to cause a buzz too, until the voltage reaches the threshold where it overcomes the hysteresis and the armature slams to the other side. It's a very different effect with the PZT disks.

Offline Monomorphic

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Re: Woodward's effect
« Reply #1204 on: 12/08/2017 06:46 pm »
Chirping a magnetic solenoid probably won't work.

I'm using a Voice Coil Actuator (VCA), not a magnetic solenoid.

Offline tdperk

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Re: Woodward's effect
« Reply #1205 on: 12/08/2017 11:49 pm »
As for the simulations, it seems to me that the asymmetric shaker mounted on an ideal thrust/torsion balance can only produce constant oscillations at the same frequency of the shaker.
Without invoking some non-ideality causing Dean drive effects there's no way to get a steady deflection, since at the end of each cycle it would go to zero.

Exactly.

Offline Monomorphic

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Re: Woodward's effect
« Reply #1206 on: 12/09/2017 12:06 pm »
As for the simulations, it seems to me that the asymmetric shaker mounted on an ideal thrust/torsion balance can only produce constant oscillations at the same frequency of the shaker.
Without invoking some non-ideality causing Dean drive effects there's no way to get a steady deflection, since at the end of each cycle it would go to zero.

Exactly.

I've already concluded that I will need to do a more thorough simulation in order to closely simulate Woodward's trace. The previous simulations have been extremely simplified. Once I include the rubber, the expansion and contraction of the PZT stack, as well as stress deformation of the aluminum beam, I think we will get a very similar effect. Fortunately, Autodesk is very generous with their learner edition/non-commercial licenses. I was able to get a 3-year learner license for the full edition of Autodesk Inventor Professional 2018 just last night for free.  This should allow us to do a full dynamic simulation of all components, including the material properties of the rubber and PZT, and Finite Element Analysis (FEA).  But it will take me a little time to get up-to-speed with another Autodesk application.
« Last Edit: 12/09/2017 01:32 pm by Monomorphic »

Offline WarpTech

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Re: Woodward's effect
« Reply #1207 on: 12/14/2017 04:47 pm »
Updated Equations

Here I relate the mass fluctuation formula to the quantum mechanical radiation reaction force and the temperature of the thermal vacuum field.

Comments?
« Last Edit: 12/14/2017 05:24 pm by WarpTech »

Offline Bob Woods

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Re: Woodward's effect
« Reply #1208 on: 12/15/2017 04:06 am »
Updated Equations

Todd, I'm the last person qualified to review your math, but I'm glad to see you pushing the edge.
Keep it up.

Offline Bob012345

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Re: Woodward's effect
« Reply #1209 on: 12/15/2017 07:01 pm »
Updated Equations

Here I relate the mass fluctuation formula to the quantum mechanical radiation reaction force and the temperature of the thermal vacuum field.

Comments?

I'm still hoping to find simpler ways to do the mass fluctuations with conventional off the shelf components. What I lack is a decent comprehension of what constitutes the right kind of energy variations that could in principle work. We know originally professor Woodward used capacitors. What about micro-mechanical oscillators? Any ideas? Thanks.

Offline WarpTech

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Re: Woodward's effect
« Reply #1210 on: 12/15/2017 07:15 pm »
Updated Equations

Here I relate the mass fluctuation formula to the quantum mechanical radiation reaction force and the temperature of the thermal vacuum field.

Comments?

I'm still hoping to find simpler ways to do the mass fluctuations with conventional off the shelf components. What I lack is a decent comprehension of what constitutes the right kind of energy variations that could in principle work. We know originally professor Woodward used capacitors. What about micro-mechanical oscillators? Any ideas? Thanks.

Lots of ideas. Just not enough time to put numbers to them and get a quantitative prediction. My concern is, my first shot at putting numbers to it resulted in forces 8 orders of magnitude smaller than what is being measured, based entirely on the charge stored on the capacitance and the above equation for FRR. Now I have some other ideas that need to be explored.

My 3rd equation above which equates Woodward's power equation to the mean square acceleration is the key, because for me anyway, it is easier to understand than the power equation.
« Last Edit: 12/17/2017 03:00 am by WarpTech »

Offline sanman

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Re: Woodward's effect
« Reply #1211 on: 12/16/2017 12:32 pm »
I'm still hoping to find simpler ways to do the mass fluctuations with conventional off the shelf components. What I lack is a decent comprehension of what constitutes the right kind of energy variations that could in principle work. We know originally professor Woodward used capacitors. What about micro-mechanical oscillators? Any ideas? Thanks.

How about focusing first on achieving a "mass fluctuation"? Moving/wiggling something back and forth along an axis is a pretty ordinary conventional well-known thing. But the idea of fluctuating mass is what's rather unconventional, since we've always been taught that mass cannot be created or destroyed. So once you get the mass fluctuation part figured out, then taking that mass/object and wiggling it along some axis would be the relatively easier part.

So we're told that increasing the internal potential energy of some object also increases its mass in some very tiny miniscule amount (since that increased energy amounts to some tiny mass).
Why not then just worry about how to achieve the most internal potential energy increase you can, using conventional off-the-shelf means?

What are the possible ways to achieve an internal energy increase? How about a chemical reaction? Aren't chemical bonds supposed to be the densest possible way to store energy? That's why we use chemical fuel for rockets, isn't it?

Is it possible to do the Mach Effect using some easily reversible chemical reaction for the internal energy / mass fluctuation part?

Offline WarpTech

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Re: Woodward's effect
« Reply #1212 on: 12/22/2017 04:31 am »
Assembly #1 complete.

Offline Monomorphic

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Re: Woodward's effect
« Reply #1213 on: 12/22/2017 11:39 am »
Assembly #1 complete.

Can you share any details such as the PZT disks used and how many, size of the brass mass, will you use rubber gasket(?), and how you plan on mounting the device?  Looks nice and clean!

I noticed your screws are set into the brass mass. Don't woodward's screws pass through the brass mass and attach to an aluminum mounting bracket?

EDIT: I think I see what you have done. You pass through the aluminum and have rubber washer/gasket on each bolt?
« Last Edit: 12/22/2017 12:32 pm by Monomorphic »

Offline WarpTech

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Re: Woodward's effect
« Reply #1214 on: 12/22/2017 05:07 pm »
Assembly #1 complete.

Can you share any details such as the PZT disks used and how many, size of the brass mass, will you use rubber gasket(?), and how you plan on mounting the device?  Looks nice and clean!

I noticed your screws are set into the brass mass. Don't woodward's screws pass through the brass mass and attach to an aluminum mounting bracket?

EDIT: I think I see what you have done. You pass through the aluminum and have rubber washer/gasket on each bolt?

1. I used SM-111 disks, thickness modulation, 50mm x 2.1mm "S" type.
2. I used conductive adhesive copper tape to put electrodes on the disks. Not so good since it's very easy to tear. I wrapped them in Kapton tape but thicker copper would be better.
3. I used carbon conductive grease between the disks, not epoxy, to minimize the thickness and maximize thermal transfer to the copper. This unfortunately allows the middle disks to slip before compression is applied, so I wrapped them in Kapton tape to hold them until it's tight.
4. There are currently 4 disks in the stack. Back to back neg, back to back pos, back to back neg, so that the end caps  and the center of the stack are positive. The two negative electrodes will allow me to test different frequencies w & 2w applied to each stack separately.
4b. Those are spring-steel cup washers under the head of the screws, not rubber. They will provide the spring-back pressure on the stack for compressive strain.
5. The objective of a shorter stack is that the thrust goes with w4 but only as dx2. So a higher frequency is better than more displacement.
6. The issue with higher frequency is that the applied power requirements also go up as w4. So a 200W audio amplifier is not going to provide enough juice. That is why I'm designing a high power pulsed source, that will ring the device to resonance, like a bell clanger.

My idea at present is to rest this device, copper side down, on one or more PZT disks, using them as a scale to weigh it. I will look for transient weight fluctuations and optimize my driver circuit. Once that's ready, I'm sure I can find someone with a precision balance to do the real tests.

« Last Edit: 12/22/2017 05:54 pm by WarpTech »

Offline Povel

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Re: Woodward's effect
« Reply #1215 on: 12/22/2017 06:42 pm »
@WarpTech

Truly a remarkable job!
Have you received any supervision/advice from Woodward & co. on the structure and on how to drive this? I ask because the copper reaction mass was one of the suggestions provided by Rodal, if I'm not mistaken.


@sanman

Quote
So we're told that increasing the internal potential energy of some object also increases its mass in some very tiny miniscule amount (since that increased energy amounts to some tiny mass)

Not sure if this is what you are implying, but from your wording it seems you are referring to a static mass increase given by special relativity (E=m/c^2).

Woodward/Mach effect is supposedly a complete different thing, a transient mass fluctuation that arises only when a non rigid object is accelerated while having its internal energy changing (this last point has been recently challenged by Tajmar, who showed that the data better agree with the model if one considers only the mechanical energy in PZT stack, not the energy stored in the electric field).

Quote
Is it possible to do the Mach Effect using some easily reversible chemical reaction for the internal energy / mass fluctuation part?

Regardless from the correctness of Tajmar's argument, I think the problem in using reversible chemical reactions is that you would get a quite noisy environment, at least if you use chemical reactions in a liquid solution (chemical reactions in solids tend to be pretty slow, and the ability to have rapid consecutive variations of internal energy is crucial for detecting the effect).
Using a fluid fluctuating mass could also produce further complications when dealing with the requirement of acceleration.

Offline WarpTech

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Re: Woodward's effect
« Reply #1216 on: 12/22/2017 07:15 pm »
@WarpTech

Truly a remarkable job!
Have you received any supervision/advice from Woodward & co. on the structure and on how to drive this? I ask because the copper reaction mass was one of the suggestions provided by Rodal, if I'm not mistaken.


@sanman

Quote
So we're told that increasing the internal potential energy of some object also increases its mass in some very tiny miniscule amount (since that increased energy amounts to some tiny mass)

Not sure if this is what you are implying, but from your wording it seems you are referring to a static mass increase given by special relativity (E=m/c^2).

Woodward/Mach effect is supposedly a complete different thing, a transient mass fluctuation that arises only when a non rigid object is accelerated while having its internal energy changing (this last point has been recently challenged by Tajmar, who showed that the data better agree with the model if one considers only the mechanical energy in PZT stack, not the energy stored in the electric field).

Quote
Is it possible to do the Mach Effect using some easily reversible chemical reaction for the internal energy / mass fluctuation part?

Regardless from the correctness of Tajmar's argument, I think the problem in using reversible chemical reactions is that you would get a quite noisy environment, at least if you use chemical reactions in a liquid solution (chemical reactions in solids tend to be pretty slow, and the ability to have rapid consecutive variations of internal energy is crucial for detecting the effect).
Using a fluid fluctuating mass could also produce further complications when dealing with the requirement of acceleration.

I took Dr. Rodal's advice and used copper instead of brass. I'm also using the same SM-111 material as Prof. Woodward. Other than that, the design is my own and the driver circuit will be my own design. First, I need to do some tests on the device to see where the resonances are, define its impedance function and see how the pre-loading affects this.

Regarding theory, I'm basically testing Woodward's theory and my own quantum theory. More on that later...
« Last Edit: 12/22/2017 07:16 pm by WarpTech »

Offline sanman

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Re: Woodward's effect
« Reply #1217 on: 12/22/2017 07:40 pm »
@WarpTech

Truly a remarkable job!
Have you received any supervision/advice from Woodward & co. on the structure and on how to drive this? I ask because the copper reaction mass was one of the suggestions provided by Rodal, if I'm not mistaken.


@sanman

Quote
So we're told that increasing the internal potential energy of some object also increases its mass in some very tiny miniscule amount (since that increased energy amounts to some tiny mass)

Not sure if this is what you are implying, but from your wording it seems you are referring to a static mass increase given by special relativity (E=m/c^2).

Woodward/Mach effect is supposedly a complete different thing, a transient mass fluctuation that arises only when a non rigid object is accelerated while having its internal energy changing (this last point has been recently challenged by Tajmar, who showed that the data better agree with the model if one considers only the mechanical energy in PZT stack, not the energy stored in the electric field).


As I understand it, Woodward/Mach effect is the alleged propulsive effect that arises from selectively varying a mass while linearly oscillating it. So the mass is higher in value on the upstroke and lower in value on the downstroke. I was just trying to dissect the situation by breaking this up into 2 things: the mass fluctuation and the linear oscillation. My point was the linear oscillation part is a fairly conventional known concept, which is the less interesting part - and meanwhile the mass fluctuation idea is the more interesting part that deserves special focus.


Quote
Quote
Is it possible to do the Mach Effect using some easily reversible chemical reaction for the internal energy / mass fluctuation part?

Regardless from the correctness of Tajmar's argument, I think the problem in using reversible chemical reactions is that you would get a quite noisy environment, at least if you use chemical reactions in a liquid solution (chemical reactions in solids tend to be pretty slow, and the ability to have rapid consecutive variations of internal energy is crucial for detecting the effect).
Using a fluid fluctuating mass could also produce further complications when dealing with the requirement of acceleration.

Okay, fair enough - so perhaps a conventional chemical reaction isn't the best candidate - but has anyone comparatively looked at all the possible candidates for physical changes that correspond to change in internal energy? Correct me if I'm wrong, but it seems like the first candidate was the electricity flow in and out of a capacitor, and then later it was purely about mechanical oscillation through piezos.

Why not make a list of all possible reversible state-changes associated with change in internal energy, and see their pro's and cons to decide which one might be the best? Are we sure that mechanical oscillation is the best way to achieve internal energy fluctuation (aka. mass fluctuation) for Mach Effect purposes?


I would also look at exploiting orthogonality of dimensions here:   imagine your idealized system is linearly oscillating along the Y-axis, then imagine the mass being oscillated is being subjected to change in internal energy via some effect occurring purely in the X-axis. This internal energy change imposed purely via the X-axis should then have no "cross-contamination" into the Y-axis, except via the associated miniscule mass fluctuation.
Do you see what I'm saying?

Offline Monomorphic

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Re: Woodward's effect
« Reply #1218 on: 12/22/2017 10:56 pm »
4b. Those are spring-steel cup washers under the head of the screws, not rubber. They will provide the spring-back pressure on the stack for compressive strain.
5. The objective of a shorter stack is that the thrust goes with w4 but only as dx2. So a higher frequency is better than more displacement.
6. The issue with higher frequency is that the applied power requirements also go up as w4. So a 200W audio amplifier is not going to provide enough juice. That is why I'm designing a high power pulsed source, that will ring the device to resonance, like a bell clanger.

Thanks for the details and clarifications. It will be interesting to see your results.  Based on my experiments reaction mass, displacement, and mounted radius of the device are the primary influence.

I completed version 5 of the asymmetric shaker just a couple of days ago to test this. The reaction mass was more than doubled from 40g to 100g and the Voice Coil Actuator (VCA) was upgraded from 3W to 20W. This 20W VCA should also have a larger displacement, but I have not measured it yet.
« Last Edit: 12/22/2017 11:05 pm by Monomorphic »

Offline Povel

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Re: Woodward's effect
« Reply #1219 on: 12/22/2017 10:59 pm »
@WarpTech

I see.
I think Woodward, Fearn at al. will be interested in your findings, since your design has some improvements they wanted to implement.



@sanman

Quote
As I understand it, Woodward/Mach effect is the alleged propulsive effect that arises from selectively varying a mass while linearly oscillating it. So the mass is higher in value on the upstroke and lower in value on the downstroke.

From the infos I have available (book, papers, etc.) that's not quite accurate. Wikipedia page definition seems consistent with what I found in the other sources:

Quote
The hypothesis states that transient mass fluctuations arise in any object that absorbs internal energy while undergoing a proper acceleration.

So technically one can have a Woodward/Mach effect without any generation of thrust.
Simply accelerating an object while changing its internal energy produces a transient fluctuation, but if you don't push and pull at the right moment there's no "momentum flux" and the center of mass stays put.
That's the reason why Woodward uses two frequencies for driving the device, one for generating the mass fluctuation by accelerating and changing the internal energy at the same time and the other, double of the first one, for pushing and pulling.


Quote
Okay, fair enough - so perhaps a conventional chemical reaction isn't the best candidate - but has anyone comparatively looked at all the possible candidates for physical changes that correspond to change in internal energy? Correct me if I'm wrong, but it seems like the first candidate was the electricity flow in and out of a capacitor, and then later it was purely about mechanical oscillation through piezos.

In Woodward's book it is said that at first the importance of the requirement of "bulk acceleration" was not understood, so initially part of trials consisted in simply charging and discharging a capacitor while pushing and pulling it, or using schemes such as the MLT (Mach-Lorentz thruster). These test often resulted in dubious or inconclusive results.

When this requirement was acknowledged it was determined that the best design between those tried before was the piezoelectric disk type.
These disks provide the acceleration and, when stacked, they also behave like capacitors, so that their internal energy can be changed. So in a way it was never about "pure" mechanical oscillation.

Tajmar paper, posted some pages ago, claims that the "internal energy" that appears in Woodward's equation is actually only the internal mechanical energy of the excited pzt stacks. In this way the predicted thrust seems to fit the data point obtained much better than the previous models.

I'm only aware of one other test using a device with a different concept.
It was suggested by Buldrini in 2011, and it consisted of a ferromagnetic mass that was accelerated through a magnetic field, kinda like in a coilgun, while its internal energy was changing due to the induced magnetostrictive stresses.
Any mass fluctuation would have resulted in a difference between the predicted and measured final displacement or velocity.

I'm not completely sure this test was actually performed. If so, the results seems to have never been published anywhere.
Here's the paper detailing the proposal.

http://www.sciencedirect.com/science/article/pii/S187538921100575X 


Quote
Are we sure that mechanical oscillation is the best way to achieve internal energy fluctuation (aka. mass fluctuation) for Mach Effect purposes?

See above, in the context of this effect fluctuating the internal energy alone (like charging and discharging a capacitor) doesn't cause the sought transient mass fluctuation.
Beside this, the problem is really what this "internal energy" means here. If only the internal mechanical energy (causally linked with the force responsible for the acceleration) is the "right" internal energy then a lot of alternatives won't work.

Quote
Do you see what I'm saying?

Maybe, but I'm not sure why you think that "cross-section contamination" is a problem here.
If you are still referring to mass fluctuation as the effect that comes out of m=E/c^2 then there is no way to use this in a isolated system for propulsion.
« Last Edit: 12/23/2017 11:20 pm by Povel »

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