I'll try some more calculations:
lets say when the tube is bubbling, the speed of sound in water is reduced by 1/3.
for stans inner tube:
length=13cm
velocity=1484m/s (sound in water)/3= 495m/s
for 1/4 wavelength resonance
f=v/4L
f=951hz

Different bubbles of different sizes have varying resonant frequencies, so it could be there are multiple frequencies they would give resonant acoustic waves.
While the tube is bubbling, I wonder if there would be a method to find resonant frequencies.
I wonder if the tube would create its own sound and be measureable with a microphone?
Perhaps the bubbles themselves would be similar to hitting the tube with an object to make it sing its resonant frequencies. Perhaps a microphone could be sat on the outer side of the water container and measure resonant frequencies?

The next question would be how to synchronise the electrical frequency to produce the dominant acoustic frequency of the tube whilst it is bubbling.

Just looking at relationship of electrical wave speed and acoustic wave speed,
this article
 http://www.hydro-international.com/content/article/underwater-electromagnetic-propagation

says:


"Above 10kHz, electromagnetic propagation is more than a hundred times faster than acoustic. ..... Doppler shift is inversely proportional to propagation velocity, so is much smaller for electromagnetic signals."
Its talking about sea water, but it might suggest doppler shift might be quite large in the acoustic waves.

here is a very good article quite recent, covering recent research on enhancing electrolysis efficiency,
http://www.jmornstein.com/documents/h2dios-reverse-fuel-cells.pdf

I was looking for info on how the h and o bubbles effect the vel factor of the electric wave, trying to find a value of dielectric for water with h and o bubbles present (the bubbles change the dielectric value).
The article devotes quite a large portion to the effects of bubbles (  and the need to remove the bubbles in order to free up electrode space for more h and o production seems to be what they are saying).
They give some values for 'e' of 0.5 but i need to convert it to the dielectric value.

turned the 'e' value was the void fraction of gas ( so approx 50% of the space was taken up by bubbles), so i dont think useful to find dielectric value of bubbling water.

heres a crazy thought:
Let assume that khz range voltage pulses along stans tubes induces acoustic waves in the water.
Would it also work in reverse?
Would pulsing acoustic waves into a metal tube filled with water induce voltage waves in the stainless tubes?

Alot of phenomena are reversible, its something to think about. If it does occur then it might be useful to match electric and acoustic resonance.

Hypothetical scenario:
lets say the layer of water right next to the tube ( bilayer) on the nanoscale, is the region of importance in the water splitting. The bulk water not playing much of a role.
If acoustic waves were to induce electromagnetic waves ( voltage waves in the tubes) then the water would need to act like a piezoelectric crystal. Solid water ( ice ) can display piezoelectric properties,
and this article shows that liquid water bilayer behaves like a solid.
http://www.nature.com/articles/srep06249

So there might be some very slim chance that if you apply a resonant acoustic wave to stans tubes,  it would induce a voltage pulse in the tubes.

That might be one way to find best frequency for the pulse network.
Might be worth a try.


Anyone want to try it on their meyer replication?

heres an interesting experiment, measuring voltages induced by cavitating bubbles in water, the experimental setup is fairly simple also.

http://www.academia.edu/2774500/Electrical_Effects_Induced_at_the_Boundary_of_an_Acoustic_Cavitation_

seems a 20khz ultrasound source induces cavitating bubbles in water

seems there is an ultrasonic method used to determine the zeta potential of substances dissolved in water. Zeta potential is related the the water bilayer ( aligned water molecules at interface of water and metals or other substances). The water is hit with ultrasonic waves, these waves cause a change in zeta potential of water bilayer, the reading is in millivolts. Its used to determine amount of colloids in wate and other things like pH.
It appears the zeta potential in volts varies in accordance with the frequency of the ultrasonic wave.
So still not sure if  hitting stans tubes will acoustic waves will give any insight into resonant frequency of electrical waves required. Still researching, will post some links shortly.

this paper has some information on using stainless steel as a tapered wave guide, for acoustic waves ( ultrasonic), figure 11 is particularly interesting, and shows a very complex wave form.
It may give some sort of guide to any acoustic waveforms in stans injector will be very complex in nature.
http://www.mdpi.com/1424-8220/15/8/19393/htm

conductivity of water  from
http://www2.emersonprocess.com/siteadmincenter/PM%20Rosemount%20Analytical%20Documents/Liq_ADS_43-018.pdf

complex paper on the water/metal bilayer, some discussions on effects of applied electric field.
Of interest the bilayer has a capacitance value.....is most of the capacitance of water only in the bilayer ( only at the level of nanometers?)
http://iopscience.iop.org/article/10.1088/1367-2630/11/12/125003/pdf;jsessionid=6D0F6AD065C28E7C2A86A2E3F4EAAD05.c4.iopscience.cld.iop.org

the breakdown voltage of water is dependent on the rise/fall time of the voltage pulse.
The shorter the pulse the higher voltage required for flashover or arc in water.
from page 22 this article
https://espace.library.uq.edu.au/view/UQ:371776/s4273717_phd_submission.pdf

if your of the view that acoustic resonance plays a role in stans tubes, then this article is quite relevant:
http://www.eecs.umich.edu/radlab/html/NEWDISS/Buerkle.pdf
Its a very indepth thesis of the physics of the interaction of acoustic waves on electromagnetic waves. It doesn't consider the creation of acoustic waves by em waves, only effect of acoustic waves on em waves by doppler shift ( frequency change of em waves by acoustic waves).
In summary:
acoustic waves produce pressure differentials in a medium, those pressure changes can effect em waves frequency ( by scattering of the em waves with a subsequent frequency shift).
So how would this relate to stans system?
lets say acoustic waves are established in the tubes, any em waves ( voltage wave is a form of em wave) will be effected by a frequency shift due to the pressure differentials.
So instead of having a constant frequency em wave, its frequency will be shifted as it transverses the differing pressures in the water.
Unfortunately the thesis doesn't consider water, but it does consider ( in depth) cylinder shapes.
There would be enough information in the thesis to make predictions of the shift in frequency expected in stans tubes. Although in the thesis it is concerned with higher frequency em waves than stan was using, the acoustic frequencies though are in the ball park.

assuming acoustic resonance plays a role in stans systems,
in the injector:
is it possible the quenching disc is not a quenching disc, but a radially slotted acoustic resonator?
Would there be any need for a quenching disc if the stop ball is already performing the function of
stopping flashback, flashback would only get as far as the stop ball which lets water in/out.
There is some vague similarity of the quenching disc to some forms of magnetron resonators
some shown here:
http://www.radartutorial.eu/08.transmitters/Magnetron.en.html

heres another thought regarding the acoustic resonance of stans tube type wfc.
There would be two types of waves:
along the length of the tubes, lets call it a longitudonal wave, and another type of wave across the water gap lets call it concentric wave. Which one would play a dominate role?
I've always thought of stans tubes in terms of the longitudonal waves along the length of the tubes, but the voltage pulse that creates the waves is extremely fast in its propogation along the length of the tube ( speed of pulse is some percentage of the speed of light, actual speed depends on what source you get the speed of em wave through water from).
Since this pulse is so fast, and the acoustic waves produced ( from expansion of water molecule due to shape change in electric field, one article suggested 10% increase in volume possible, sorry cant remember source ) are travelling at normal speed of sound in water ( quite slow),
it might be reasonable to assume the water reacts all the way along the length of the tube instantaneously ( although its some percentage of the speed of light, very fast).
If we assume the whole tube rings instantaneously, then the concentric waveform might be assumed to be the dominate resonant mode.
So the width of the water cylinder ( inbetween metal tubes) might play a larger role than the longitudonal length of the tubes?
Stan has obviously matched the tubes acoustic resonant frequencies by cutting a slot in the outer tube ( the slotted part is effectively removed from the resonant vibration).
So that is related to the longitudonal resonance, the tubes natural ringing frequencies are matched. But that wavelength is extremely long, way way longer than the tubes, and I'm guessing not playing a huge role in resonance. The fact both tubes have same ringing frequency though might play a role in the concentric resonance. But the width of the water gap will also be important.
A single hollow cylinder filled with water is easy to visualise the standing waves, just concentric rings,
but having an  inner tube might complicate the standing wave pattern. I'm not sure if it will still be concentric ring shape, perhaps something more complex. Lets assume its still a concentric ring shape,
Where would you want the maxima nodes to be located? I would think if possible  concentrate the standing waves at the outer edge of the water, at the water/metal interface where the gas is being produced ( I think 1/2wavelength would do that) ( I've heard a report of someone seeing bubbles being produced in the middle between the tubes, but I haven't seen any videos of that occuring, can anyone point me in direction of someone who has seen bubbles being formed in the middle of the tubes ( half way between electrodes?). That would require different maxima point.
I'm of opinion splitting occurs at the metal water interface. Where the water capacitance is also formed on the nanometre scale ( helmholtz layer).

So some basic calcs for concentric resonant waves ( acoustic):
speed of sound in water = 1482m/s wavelength = vel/freq

lets say 5khz frequency of pulses
1482/5000=0.29
wavelength=0.29m ( 29cm) 1/2 wavelength=0.148m ( 14.8cm)

10khz
1482/10000=0.14m (14cm) 1/2 =0.07m ( 7cm)

15khz
1482/15000=0.0988m ( 9.8cm) 1/2=0.0494m ( 4.94cm)

20khz
1482/20000=0.0741m (7.41cm) 1/2=0.03705 (3.7cm)

So 20khz would give 3.5cm gap between tubes to give concentric resonance with maxima
occuring at inner surfaces of tubes. Which does not match with the water gap distance stan used. A bit of a dilemma!
( assuming simple concentric resonance occurs with hollow tube within hollow tube format).
( note original post had some errors in dimensions which I've now revised, so numbers above should be correct)

Another research paper, they found voltage pulses required to be 150v to 300v for acoustic waves to be generated in water, sorry didn't remember to note the source.

for injector style wfc:
water gap = 0.01inch ( 0.254mm) water gap
using formula previous post
f=vel/wavelength
f=1482/2*0.254 mm
f=1482/0.00508m
f=291,732hz
f=292khz
that would be lowest frequency to give maxima at voltage zone metal surfaces for concentric ringing. Thats a pretty high frequency if concentric ringing plays a role, in ultrasound range I guess. Certainly ultrasound is used for acoustic imaging, cavitation etc in water.

just some articles that might have relevance to stans systems:

relates to acoustic wave influence on water droplets, they can be manipulated in space to the maxima nodes in a concentric waveguide. If stans injector does have water droplets in the voltage zone, those droplets can be concentrated at the maxima of acoustic waves.
https://www.researchgate.net/figure/233814248_fig3_FIG-3-Two-drops-levitated-in-a-hollow-PZT-cylinder-Gravity-is-acting-in-the-downward

Just an experiment that shows acoustic wave reflection within a tube see fig7
http://www.mdpi.com/1424-8220/13/3/2777/htm

Interesting article on water having zero refractive index ( converting surface waves to compressional waves) not sure of relevance to stans system.
http://www.nature.com/articles/srep06979

This article shows light waves bending around 90 degree bends using zero refractive index material. Puting this with last link ( water can act as zero refractive index material), it might
be possible stans injector water jacket section is being supplied with waves from the quenching disc area. Plus a reflection would occur at the threaded end for 0-ring.
http://www.nature.com/nmat/journal/v10/n8/fig_tab/nmat3030_F3.html

ultrasound wave in water pipe, bending at 90degree intersection see fig2
http://www.twi-global.com/technical-knowledge/published-papers/long-range-inspection-of-engineering-assets-using-guided-ultrasonic-waves-september-2008/

I've been searching for waves propogation around right angle bends ( channels),
this article section 4.1 details conditions where it can occur.

https://www.researchgate.net/publication/258666489_Solitary_Waves_in_Open_Channels_with_Abrupt_Turns_and_Branching_Points

If the water jacket in stans injector is involved with acoustic resonance it would require waves to go around a right angle bend. It appears this can occur when the width of the channel is small in relation to wavelength, with little loss of wave energy.

It depends on which dimensions you use in stans diagrams. But if there is a 0.01inch gap between the quenching disc and the outer housing, it provides are narrow channel then a right angle bend into the water jacket which is 10times as wide as the narrow channel.
Now I think there is a possibilty the water jacket plays a role.

It would be possible to build a ripple tank, matching stans dimensions ( in cross section) and get some idea what the acoustic waves are doing. If there is no 0.01" gap between the quenching.

Below two pictures of the two possible scenarios based on stans dimensions:
(i've drawn up close view of the voltage zone/quench disc/water jacket
First picture shows continuous water zone which might act as acoustic resonant area ( not just voltage zone) via wave transfer. )A 0.01" gap between quench disc and outer stainless housing.
Second picture shows outer stainless steel housing up tight against the quench disc, water would still seep through the metal on metal inner/outer housing portion ( where they are hard up against each other), but would mean outer water jacket not involved in acoustic resonance as there is no continous connection of water between voltage zone and water jacket.

possible scenarios of concentric waves;
first pic: shows acoustic waves possibly going into water jacket zone
( goes with first pic above). Water jacket involved in acoustics ( reflections off the quenching disc, and o-ring thread will complicate it). Only showing small part of the acoustic wave in voltage zone for clarity.
second pic: shows concentric acoustic waves only in voltage zone
( goes with second pic above), I've only shown waves on one side of voltage zone for simplicity.
( longitudonal acoustic waves not considered in these pics)

with regard the possibility of waveform1 above:
the narrow channel which joins to the water jacket, could be visualised as similar to these animations:

http://resonanceswavesandfields.blogspot.com.au/2013/06/315-resonant-scattering-of-waves-one.html#fig36

A narrow hole ( 0.01" gap between outer housing and quenching disc) acts as narrow waveguide,
which joins to larger resonator via right angle turn. Its a very similar situation to what is occuring in the animations shown on above link.

new vid posted by valentin petkov ( valyonpz ), modified circuit also.
"  https://www.youtube.com/watch?v=LgqhE_ouuM0  "
showing input 150v  at 70mA

just looking over this article:
http://www.nature.com/articles/srep06596
which looks at water in high electric fields.
Its looking at how much the angle between the hydrogen and oxygen changes with electric field strength.
Table 1 gives some interesting data ( they give volts/nanometre which I've converted to volts/mm) to make it easier to compare to stans systems.
At 100,000volts/mm cosine of the angle is 0.11, at 200,000volts/mm cosine of the angle is 0.191
( you can convert to the actual angle using inverse cosine).
Anyhow, what it is showing ( if i'm correct) is that the stretching of the water molecule by angle change of the hho molecules, requires very high electric field. In stans systems due to the much lower voltages the change in the angles of the water molecules will be very low.
But.........as far as I can tell, the water molecules in contact with the stainless steel ( only a few nanometres in thickness), experience a very different electrical field. Even when there is no external voltage, there can be alignment of the molecules due to the free electrons in the metal,
and the electric field strengths can be quite high, even when no voltage applied.
So the area that matters most  ( helmholtz layer) the electric field strengths may be way higher than the applied external field. That might also apply to any acoustic pressure waves, which on a nanometre scale the pressure differentials might be quite high.
So what is occuring on the scale of a single water molecule is very different to the fields/pressures we can measure with multimeter etc.
The above link I think would tend to confirm the bulk water is playing little role in the water splitting process.

a new vid from valentin petkov
"   https://www.youtube.com/watch?v=YlmaFLSZObM   "
very interesting video showing the injector coil ( he calls it meyers 'big coil'), he shows waveform
as stephens meyers waveform shape, resonance around 200khz. I wonder with 'big coil' there is no need for gap in the core under primary? I think this is first time I see anyone posting waveform of the injector coil? Great work valentin!

Quote from brettly on February 14th, 2016, 03:20 AM

a new vid from valentin petkov
"   https://www.youtube.com/watch?v=YlmaFLSZObM  "
very interesting video showing the injector coil ( he calls it meyers 'big coil'), he shows waveform
as stephens meyers waveform shape, resonance around 200khz. I wonder with 'big coil' there is no need for gap in the core under primary? I think this is first time I see anyone posting waveform of the injector coil? Great work valentin!

an open c-core as shown in the video is acting more as a rod or a core with almost infinite air gap.
a gap working like a gap is always in the << 1mm range.

thanks gunther.
Just going back to my diagram waveform1
which depicts an option on the injector structure ( according to stans dimensions).
I've looked at a video on radar waveguides ( since stans work might have been influenced by
radar knowledge)

https://www.youtube.com/watch?v=d73d3zY8T5Q
The section on choke joints ( joints in radar waveguides), I cant help but see some similarity to
the waveguide1 option. Where the inner waveguide is surrounded by a sort of backwards facing slot of 1/4wavelength. Its a very interesting design within itself even if not related to stans work.
Also the video states that 2times wavelength bends are required to minimise reflections around 90 degree bends. Also I realise stan clearly states the quenching disc purpose is for stopping of flashback, but i'm still wondering if that is really its purpose, especially if waveform1 structure is the intended correct dimensions of the injector. The 'error' in stans dimensions really does pose a difficult question of what the exact structure of the injector is intended to be.
Is there a possibility the injector structure is more complex that initially thought when the diagrams were first published on esforum?