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Thread: EHD Model of Tornadoes

  1. #31
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    One thing at a time, The high rate of water uptake over lakes suggests to me not an enormous latent heat flow at the base but the transport of water droplets upwards which would represent a continuous sink of energy cooling the vertical flow and reducing pressure thus supporting the inflow of air at all points of the upflow. The inflowing air conventionally has rotation to start with so the angular momentum would be expected to cause acceleration of the spin rate and thus pressure drop toward the centre and heating, the heating would tend to increase pressure and be self limiting. So it is not surprising that the tornado seems to increase over water if it is a cooling sink.

    I am in no way challenging your hypothesis which I find interesting actually I am wondering what experiment could be devised to test it.

  2. #32
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    Well, I would avoid the "all ur science are belong wrong" approach to start with. Show that an EHD tornado replicates and doesn't contradict any measurements made. Prove it is a feasible model first, then look for how you can distinguish between it and other models.

    There is merit in working through the model based on that one assumption (inflows are charged) even if it turns out to be a bad assumption. It might have applicability in other environments, or under certain conditions.

    I think the issue is that right now what you are doing is saying "this looks like this, I say our current model is broken and my solution is the only one that works". Makes it easier to ignore, in a way.

    Good luck, anyway. I am not qualified to dig too deeply into this one so I will sit on the sidelines.

  3. #33
    Here are a couple of approaches to testing this theory.

    First, no one has ever successfully created a bottleneck vortex in an open apparatus. The experiments described in the OP relied on a sealed chamber to get all of the air to flow through the hole in the bottom (see this image: Vortex Apparatus). The present contention is that a bottleneck vortex could be created in an open apparatus if the inflow is charged, and if it is flowing above a solid conductor that can develop an induced opposite charge. Plans for an apparatus to test this are here. I would have built this thing already, but I don't know enough about high voltage to spec the electrical components, and all of the EEs I have contacted don't understand what I'm trying to do. Anyway, eventually I'll find somebody who can finish the specs, and then I'll build & test it.

    Another approach would be to do a field study. I mentioned previously that the essential ingredient is charged inflow, and that nobody has done a space charge study to make or break the contentions in question. So the most obvious place to start is with a... space charge study!

    This would be easiest to do on a waterspout. They are typically weak, and therefore pose little risk. They are also easy to catch. In waterspout season (late summer to early fall off the Florida Keys) there are hundreds of them each year. A high-speed motorboat chasing waterspouts can travel faster than is legal on any road in the U.S., and on the open sea, a boat can go straight toward the objective (not having to follow the roads that don't head directly toward the intercept point). The theory also predicts that the space charge density should be higher, due to the conductivity of the sea, so the results should be more dramatic. And there is another very important advantage to waterspouts. The sea itself provides an enormous amount of information about the flow field. Consider the following image:

    Waterspout with banded inflow off the Florida Keys, 1969-09-10, credit Joseph Golden, courtesy NOAA

    The first thing that we notice about the inflow is the cyclonic pattern. This is expected, but there is something that is very unexpected about this. For those who have not spent a lot of time on the water, darker water means faster winds. So this image is not telling us that we have an axisymmetric inflow in response to a low pressure at the base of the vortex. Rather, it tells us that there is a discrete inflow channel that is supplying all of the air to the vortex. This is totally unexpected in fluid dynamics. Channeling is evidence of a difference in viscosity, but there shouldn't be any way of getting that much difference in the air, which is generally well-mixed. So all of the air should be at roughly the same viscosity, and hence it should flow at the same rate, as it will all experience the same amount of friction. Now look closely at the image. The researchers successfully deployed two flares to gather more information on the flow field. Outside of the high-velocity (darker water) channel, the air isn't even flowing toward the vortex. So all of the inflow is in a discrete channel. This can only be evidence of charged air, which has a much lower viscosity than neutral air.

    The theory in question predicts that outside of the high-velocity channel, the air should be neutrally charged, while inside the channel, the air should be bearing a space charge of 10-4 C/m3. That would be 5 orders of magnitude greater than typical charge densities inside thunderstorms. The theory also predicts that the inflow should be as much as 5 C warmer than the surrounding air -- so warm, in fact, that its buoyancy should obligate it to rise above the surface, proving that the electric force is overpowering its buoyancy.

  4. #34
    Quote Originally Posted by Shaula View Post
    Good luck, anyway.
    Thanks!

  5. #35
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    first thanks for the picture references which are interesting. The waterspout clearly has water (not vapour) rising in a column which we assume has air rotation all round it but invisible. The rotation near the sea surface has caused a spiral pattern. The flares apparently flowing outward are strange. In themselves I do not see how they suggest an electric effect. The cold air falling must have a boundary where the flow is too great to enter the vortex and it flows outwards. If the central falling column of cold air is the medium of angular momentum moving toward a central stick of high speed low pressure air it makes sense that at a certain diameter the pressure drops enough to suck water upwards. I have seen a twister start near me , I was in a boat, and it definitely looked like spinning air at the base of a black cloud which reached downwards untilit touched ground (beside the boat) Having touched down it seemed to stick and travelled towards me and hit our boat. There was a very high wind veering and no electric feeling at all.

  6. #36
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    Quote Originally Posted by CharlesChandler View Post

    The extreme low pressure at the ground is the source of the destructive power of the tornado...
    Now I have to disagree with you on that one:
    http://www.stormtrack.org/library/damage/goshen.htm
    "The winds which toppled the sanctuary came from the south direction actually preceded the tornado centerline and was on the periphery of the tornadic circulation." Inflow jet most likely.

    Improper construction is the problem. Low pressure really doesn't make the house explode. Most windows are broken open, and a rush of air actually inflates the house (more high pressure) and the winds just tear things up normally in most cases. If anything, if solid shutters could be fastened over windows when a PDS watch is issued (don't waste time closing windows during a warning) and the house is well constructed, there should be less damage. I think there was a magazine here locally showing well constructed homes which survived--but perhaps they were not hit by the suction spots as Fujita called them. In any event a lot of people waste time closing windows. The discussion now is maybe only doing warnings on supercell tornadoes to prevent the cry-wolf effect, getting people to wear helmets, and debris balls on radar...

    BTW don't seek shelter under overpasses. That blasted video made of the small funnel during the Andover event had gotten people killed in May of 1999 at Moore. Before then, I remember even Tim Marshall on Oprah (around the time TWISTER opened in theaters) talking about hiding in one. Now--to be fair--he chose one where he disappeared between closely spaced girders IIRC. But at Moore, folks were exposed under slab concrete with nothing to protect them. If anything, a wind tunnel effect can make things worse.

    BTW nice footage of the bus inside the Henryville tornado here:

    http://abcnews.go.com/blogs/headline...er-saves-kids/

    http://charles-chandler.org/Geophysi...tornadoes).jpg
    Looks Lovecraftian...like this
    http://www.youtube.com/watch?v=5ohIV...layer_embedded
    http://www.stormtrack.org/forum/show...ernal-Vortices!!
    http://www.stormtrack.org/forum/show...ht=Bus+tornado

    Do you think the pinch off of vortex breakdown be useful for hot fusion if they use vortices instead of a racetrack method?
    http://charles-chandler.org/Geophysi...rtexes%203.png

  7. #37
    Quote Originally Posted by profloater View Post
    The flares apparently flowing outward are strange. In themselves I do not see how they suggest an electric effect.
    The fact that the flow field is not axisymmetric, and that most or all of the inflow is inside a discrete channel, is evidence of... channeling. Now, in fluid dynamics, what does a channeled inflow prove? It proves a major difference in viscosity. How do you get a major difference in viscosity in the air? Typically, there are only two factors in the air that affect viscosity: temperature and humidity. But within the relevant ranges, there is only a 6% difference in kinematic viscosity, from the coolest, highest-humidity air to the warmest, lowest-viscosity air.

    Kinematic Viscosity of Air
    ( 10−5 m2/s)
    100% RH 0% RH
    20 C 1.527 1.531
    30 C 1.617 1.625

    And yet in the image, we can tell from the color of the water that air outside of the channel is barely moving (perhaps at 1 m/s), while inside the channel, the speeds could be something like 20 m/s. Remember also that skin friction varies with the square of the velocity. So the air inside the channel is experiencing 400 times more skin friction, roughly speaking. That's not going to happen because of a 6% difference in viscosity due to temperature and humidity. This can only be evidence of some other factor that created extremely low viscosity air that could channel that fast through stationary air. And there is only one other factor: electric charge, which lowers viscosity by preventing the particle collisions that instantiate friction, and by raising the threshold for turbulence.

    Then, if the air has that powerful of a charge, how does it ever break away and head upward? The electric force should be far more powerful than the buoyancy, which is a function of gravity. Yet if the space charge is neutralized, the electric force is no longer a factor, and the air is free to ascend.

    So unlike other EM theories, I'm not saying that the electric force is helping the updraft, as if it was a Coulomb force that was pulling the air toward the cloud. Rather, it's the opposite. The electric force is fighting the updraft, holding the air down, until charge recombination occurs. Then the air rises vigorously, having just gotten past the bottleneck caused by the electric force.


    Quote Originally Posted by profloater View Post
    The cold air falling must have a boundary where the flow is too great to enter the vortex and it flows outwards.
    There isn't any evidence of a downdraft from evaporative cooling. In extreme cases where there is a mist funnel, it behaves just like a debris funnel over land, and reveals that the air outside of the vortex (within 100 meters) is either stationary, or rotates very slowly, with no downdrafts. So while evaporative cooling certainly absorbs some of the heat at the base of the vortex, it does not cause any local recirculation of air.

    Quote Originally Posted by profloater View Post
    There was a very high wind veering and no electric feeling at all.
    I wouldn't expect an electric feeling at the proposed charge densities. The high-end number that I'm using for the space charge is 6.25  10−3 C/m3, which is 1 PPM. This is roughly the amount of space charge developed by household ionizing air purifiers, which don't produce any noticeable physical sensation.

    Quote Originally Posted by CharlesChandler
    The extreme low pressure at the ground is the source of the destructive power of the tornado...
    Quote Originally Posted by publiusr View Post
    Now I have to disagree with you on that one. "The winds which toppled the sanctuary came from the south direction actually preceded the tornado centerline and was on the periphery of the tornadic circulation." Inflow jet most likely.
    I agree that it was an inflow jet. Furthermore, my construct can explain inflow jets, as described above. And the extreme low pressure at the base of the vortex is the source of the energy in the inflow jet.

    Quote Originally Posted by publiusr View Post
    The discussion now is maybe only doing warnings on supercell tornadoes to prevent the cry-wolf effect, getting people to wear helmets, and debris balls on radar...
    There is definitely a cry-wolf effect. The raw number for the false alarm rate is 77%. But that's only part of the story. 74% of all tornadoes are < EF2 in strength, and which are responsible for only 4% of the tornado-related fatalities. If we considered it to be a false alarm if an EF2+ tornado (capable of posing a real risk to the public) did not form, the false alarm rate would be 94%. At statistics like that, people in Tornado Alley don't pay much attention to tornado warnings (much less watches), and it's arguable that NWS's efforts to date have been largely ineffective.

    Furthermore, nobody is expecting the situation to improve with the existing strategy. Doppler radar gives us the ability to detect rotation inside the cloud, revealing the presence of a mesocyclone. But the false alarms are coming from the 75% of all mesocyclones that do not produce tornadoes. Curiously, the two most powerful mesocyclones on record did not produce tornadoes. So the relationship between mesocyclones & tornadoes is indirect. I'm guessing that 10 years from now, when the false alarm rate for all tornadoes is still 77%, and for EF2+ tornadoes is still 94%, then maybe meteorologists will concede that another factor has to be present. Then we'll have some progress.

    Quote Originally Posted by publiusr View Post
    BTW nice footage of the bus inside the Henryville tornado here.
    Videos and eyewitness reports of things like this were what got me to start considering the possible effects of EM forces. Look carefully at the video. The tilting and pitching of the bus prove that the bus was lofted above the ground. And yet the bus didn't get rolled. Now watch any of the YouTube videos (such as this) where they show what happens when cars or school buses are lofted by the exhaust from jet engines. They don't hover -- they get rolled violently. This cannot be simple aerodynamics. So what other forces are present?

    Quote Originally Posted by publiusr View Post
    Do you think the pinch off of vortex breakdown be useful for hot fusion if they use vortices instead of a racetrack method?
    Ummm... what?

  8. #38
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    In hot fusion tokamaks, the plasma forms a doughnut or race-track. I was thinking that a vortex model might help

    Here at the curent weather thread, are some very dusty tornadoes from mexico
    http://www.bautforum.com/showthread....14#post2003814

    I wonder if that was double core, like the haydevil we saw on Grazulis Tornado Video Classics. The weather channel needs to pay him to scour you-tube for proper documentaries. As it is, you see a second or two of the funnel, and everything else is human interest--the same old pictures of debris which don't interest me. I know that sounds hard hearted, but its the funnel itself that needs to be the focus.

    A recent thread you may find of interest: http://www.bautforum.com/showthread....lonimbus-cloud
    http://blogs.discovermagazine.com/ba...dancing-cloud/

    Now its easy to say that it isn't simple aerodynamics, but there are many lines of attack for the wind. We think there is a strong up draft along the outer envelope. Ironically, there was once a time when people believed that tornadoes did not rotate. The old Stapelton airport (shown in Grazulis book Significant tornadoes) shows no condensation funnel (not so unexpected--one was shown by KFOR moving a car off the interstate) and a plume of material rising upward. But you can tell this is mechanical forces by the way the debris tears. It would have looked different if it had been mostly an electrical effect.

    Horizontal vortices show upward air. Combine two different air flows in the same storm and objects large enough to be caught between two suction spots and the up-draft may seem to hover and spin around a bit.

    More study is needed in any event.

    Now I do seem to remember ball or bead lightning--corna discharge that Klass wrote a book on--forming on power lines near very powerful tornadoes...

    Now I did write a fictional short story called CHASE SEASON where I suggest that the March 1925 tri-state--which did run near its parent Low and catch up with it while running atop a ridge--was feeding off a ley line, capacitor parks, the winds of the Zarr, and how it was the father of what we saw in THE DUNWICH HORROR.
    Last edited by publiusr; 2012-Apr-01 at 07:28 PM.

  9. #39
    Quote Originally Posted by publiusr View Post
    In hot fusion tokamaks, the plasma forms a doughnut or race-track.
    Tokamaks create nuclear fusion by compressing the plasma. A vacuum vortex decompresses the gas. Sounds like they'd be mutually exclusive.

    Quote Originally Posted by publiusr View Post
    I wonder if that was double core, like the haydevil we saw on Grazulis Tornado Video Classics.
    The "double core" is another aspect of tornadoes directly addressed by my model, and which has no fluid dynamic explanation. Just on the basis of aerodynamics, the amount of dust lofted by a tornado is hard to understand. I'm saying that the tornadic inflow is positively charged, which induces a negative charge in the Earth. The electric force then helps loft dust and debris into the inflow. And if the lofted particulate matter doesn't fully neutralize the positively charged air, the electric force persists, though the particles will get centrifuged outward, forming a sheath around the vortex.

    Quote Originally Posted by publiusr View Post
    But you can tell this is mechanical forces by the way the debris tears. It would have looked different if it had been mostly an electrical effect.
    Indeed, but what causes the mechanical energy?

    Quote Originally Posted by publiusr View Post
    Horizontal vortices show upward air. Combine two different air flows in the same storm and objects large enough to be caught between two suction spots and the up-draft may seem to hover and spin around a bit.
    Can you explain this in mechanical terms?

    Quote Originally Posted by publiusr View Post
    Now I do seem to remember ball or bead lightning--corona discharge that Klass wrote a book on--forming on power lines near very powerful tornadoes...
    Here's a recent example of corona discharges from pointy objects near a tornado:

    Orange flashes following tornado in Chattanooga, TN, 2010-10-28, courtesy U.S. Army Corps of Engineers.

    The "explanation" was that the lamp-posts caught on fire. Interestingly, the lamps were not damaged by the "fires." It's also curious that the "fires" were vertically oriented, even though the 40+ m/s winds were traveling horizontally.

  10. #40
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    I can't help if that was water on the camera--hard to tell.I have bad eyes and I hate digital cameras. What I would like to see is a multi-camera rig with old VHS, digital, and film cameras in a row. If something is seen by all three, it's real--most likely.

    Maybe the folks over at www.stormtrack.org might help you, as they are rather more knowledgeable than I am. We may not need another sterling colgate. Cheaper drones are coming out, and maybe Reed Timmer or Sean Casey could put some of his instruments inside a vortex. BTW, I have been looking for footage of the actual funnel of the night tornado that struck nearby. I saw it one time on the TV news, and haven't see it again. This was the Center Point/Clay event from this:

    http://en.wikipedia.org/wiki/January...rnado_outbreak

    I don't suppose you have it somewhere? All they do are debris stories now.

  11. #41
    Quote Originally Posted by publiusr View Post
    I can't help if that was water on the camera--hard to tell.
    Water droplets on the lens could certainly have smeared the light source. But would they have turned it orange?

    Here's another case that's easier to see, though the thunderstorms didn't produce any tornadoes. A bow echo moved through Fort Worth, TX, a little over a hour before the flashes. In my model, the rear flank downdraft is positively charged, and I'm contending that the combined downdrafts from the bow echo accumulated until the potential was sufficient for corona discharges (> 100 kV/m). The flashes occurred where high-power transmission lines cross the Trinity River. I'm thinking that the charged air was clinging to the conductivity of the water, and the power line towers were the pointy objects that set off the huge discharges.

    Corona discharges in Fort Worth, TX, 2011-05-10, courtesy Brian Luenser. video, photo 1, photo 2, photo 3.

    Quote Originally Posted by publiusr View Post
    We may not need another Stirling Colgate.
    Please explain.

    Quote Originally Posted by publiusr View Post
    Cheaper drones are coming out, and maybe Reed Timmer or Sean Casey could put some of his instruments inside a vortex.
    The National Weather Service, in collaboration with a number of other organizations, recently spent over $12 million on VORTEX2, the largest and most ambitious field study of tornadoes ever conducted. They had 150 people in the field for 13 weeks, deploying several hundred pieces of instrumentation. Yet in all of that, there wasn't one single electric field meter or magnetometer. That's zero EM instrumentation, in the largest field study of thunderstorms ever conducted.

    Why is that?

    Quote Originally Posted by publiusr View Post
    I have been looking for footage of the actual funnel of the night tornado that struck nearby.
    I haven't snagged anything on that event. And like you, I find it frustrating when videos only show a couple of seconds of the tornado, interspersed with another 59 minutes of human drama. If the storm chasers don't find any tornadoes, they can still get 60 minutes of footage if they create the drama with a little in-fighting amongst themselves. One of these days, they'll do a whole show of nothing but Reed and Sean in the octagon, to see who is the better chaser.

  12. #42
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    I'm late to this thread, so apologies in advance if my questions have already been answered.

    First: why post this idea here, in BAUT? I mean, it's rather loosely connected with space and astronomy (and that's being generous), so you're not likely to get too many deep questions on it. Specifically, your idea does not "go against or beyond commonly-held astronomical theory". Or does it? If so, would you please state what such theory, or theories, it goes against or is beyond?

    Follow-up question: what other science-based fora have you posted your ideas in (or considered posting in)?

    Quote Originally Posted by CharlesChandler View Post
    The only "non-fluid dynamic forces" in the atmosphere (and especially in thunderstorms) are electromagnetic.
    Is gravity a "non-fluid dynamic force"?

    So while the vacuum vortex is caused by fluid dynamic factors (i.e., the low pressure inside the cloud), the constriction of the radius at the ground can only be due to EM factors, as they are the only other physical forces present.
    Does this mean that, according to your idea, that "the constriction of the radius at the ground" can occur in zero-g environments?

  13. #43
    Quote Originally Posted by Nereid View Post
    Why post this idea here, in BAUT?
    Hi Nereid! An obvious question, but it does have an answer. First, where else am I going to post EHD theories? Meteorologists don't know anything about it. Even geophysicists do not study interactions between electromagnetic and fluid dynamic systems. But at least some astrophysicists are versed in EHD. Second, I was going to tie into a broader body of theory that also includes mirages and dust devils, but I forgot about the "one ATM thread at a time" rule, and my dust devil thread got locked, which is a bummer because that was the one aspect that was sorta relevant, since NASA has been studying dust devils on Mars. Anyway, I was going to segue into the larger body of EHD astrophysical theory that I've been developing (accretion, solar theory, etc.), but at 30 days per thread, that's going to take a long time!

    Quote Originally Posted by Nereid View Post
    Follow-up question: what other science-based fora have you posted your ideas in (or considered posting in)?
    I have also posted on the JREF and thunderbolts boards, but the most learned responses that I've gotten have been from plasma physicists here.

    Quote Originally Posted by Nereid View Post
    Is gravity a "non-fluid dynamic force"?
    The traditional meteorological framework includes heat sources and sinks which alter the density of the air, which in the presence of gravity results in airflows, which can be quantified in fluid dynamic terms. A meteorologist takes all of this for granted, but I should have spelled it out for a non-meteorological crowd. So what I was trying to say was, "Having considered the inertial, viscous, thermal, and gravitational forces operative in the air, the only other forces are electromagnetic."

    Quote Originally Posted by Nereid View Post
    Does this mean that, according to your idea, that "the constriction of the radius at the ground" can occur in zero-g environments?
    There would be a number of differences in a zero-g environment. For instance, buoyancy wouldn't be a factor, which figures significantly in the dynamics of tornadoes and dust devils.

  14. #44
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    Quote Originally Posted by CharlesChandler View Post
    Hi Nereid! An obvious question, but it does have an answer. First, where else am I going to post EHD theories?
    Dunno, but this kind of logic seems a bit, um, odd.

    Kinda like this: I have an ATM idea concerning geraniums. I found this cool microbiology website, all about bacteria and viruses. I think I'll post it there. When someone asks, "why are you posting here?" I'll reply "where else am I going to post geranium theories?"

    Oh, and what does "EHD" stand for?

    Meteorologists don't know anything about it. Even geophysicists do not study interactions between electromagnetic and fluid dynamic systems. But at least some astrophysicists are versed in EHD.
    They are?

    Can you give some examples please?

    Second, I was going to tie into a broader body of theory that also includes mirages and dust devils, but I forgot about the "one ATM thread at a time" rule, and my dust devil thread got locked, which is a bummer because that was the one aspect that was sorta relevant, since NASA has been studying dust devils on Mars.
    Isn't atmospheric physics a (sub-)field?

    Anyway, I was going to segue into the larger body of EHD astrophysical theory that I've been developing (accretion, solar theory, etc.), but at 30 days per thread, that's going to take a long time!
    In hindsight, perhaps you could have gone about this the other way round?

    Quote Originally Posted by Nereid
    Follow-up question: what other science-based fora have you posted your ideas in (or considered posting in)?
    I have also posted on the JREF and thunderbolts boards, but the most learned responses that I've gotten have been from plasma physicists here.
    Well, that last part is quite interesting.

    You may find JREF a more suitable forum than BAUT. Funny that you added "and thunderbolts"; whatever that is, it's most certainly NOT science-based!

    Is gravity a "non-fluid dynamic force"?
    The traditional meteorological framework includes heat sources and sinks which alter the density of the air, which in the presence of gravity results in airflows, which can be quantified in fluid dynamic terms. A meteorologist takes all of this for granted, but I should have spelled it out for a non-meteorological crowd. So what I was trying to say was, "Having considered the inertial, viscous, thermal, and gravitational forces operative in the air, the only other forces are electromagnetic."
    Perhaps your readers, here at least, would have understood you better had you included that, in the OP?

    Does this mean that, according to your idea, that "the constriction of the radius at the ground" can occur in zero-g environments?
    There would be a number of differences in a zero-g environment. For instance, buoyancy wouldn't be a factor, which figures significantly in the damics of tornadoes and dust devils.
    Perhaps, given that meteorology is not often discussed in BAUT, your OP could have included some background material? You know, general scope, links to review papers on current theory, that sort of thing.

    Which leads to this question: to what extent have terrestrial tornadoes been successfully modeled? As in either computer-based simulations (based on boundary conditions and sets of equations), or in scaled-down 'in the lab' simulations (or both).

  15. #45
    What does "EHD" stand for?
    Electro-hydro-dynamics. Here is a good description of the more all-encompassing EMHD:

    Electro-Magneto-Hydro-Dynamics (EMHD) addresses all phenomena related to the interaction of electric and magnetic fields with electrically conducting or magnetic fluids. Electric and magnetic flow control, for example, is a challenging area of mathematical and engineering research with many applications such as the reduction of drag, flow stabilization to delay transition to turbulence, tailored stirring of liquids, pumping using traveling EM waves, and many others. The application of electric and magnetic fields in diverse branches of materials science such as crystal growth, induction melting, solidification, metal casting, welding, fabrication of nanofibres, fabrication of specialty composites and functionally graded materials, or ferrofluids is recently of growing interest. Fully coupled EMHD systems, that is, in situations where the flow-field is influenced by the electric and magnetic fields and where these fields are in turn influenced by the flow-field, are challenging research subjects with applications in geo- and astrophysics (dynamo, magneto-rotational-instability, etc.). Numerical simulations of many important processes (the growth of single crystals, metal casting for aerospace applications, aluminum electrolysis, etc.) require sophisticated tools for coupled fluid flow ~ heat/mass transfer ~ electromagnetic fields. In summary, computational EMHD is a vital subject of recent research with a long list of interdisciplinary applications and scientific problems.

    Source: Gerbeth, G., Dulikravich, G. S., and Pericleous, K., 2008: Computational electro-magneto-hydro-dynamics (EMHD). 8th World Congress on Computational Mechanics (WCCM8), Venice, Italy
    If you know of a board that has more people who know about this kind of stuff, and that tolerates new ideas, please let me know!

    Quote Originally Posted by Nereid View Post
    Funny that you added "and thunderbolts"; whatever that is, it's most certainly NOT science-based!
    I find it difficult to put the thunderbolts board into a category. Certainly a lot of it is way non-scientific. Then again, there are some very knowledgeable, open-minded people there, who have been very generous with suggestions. Most of all, they think that a bulletin board is an opportunity to do online collaboration, instead of online swarming and stomping. But they didn't like my tornado theory, because they had already locked down on a Velikovskian idea, that tornadoes are EDM (electric discharge machining) on a planetary scale. So while they helped me a lot when I was first learning EM theory, due to their patience, generosity, and open-mindedness, I eventually went my own way, because I settled on a more mechanistic construct.

    The JREF board is all of the way the other way. They attack people because that's what they do. Every once in a while, if they can't beat somebody down with rhetoric and gang tactics, they'll resort to a legitimate attack on the actual assertions being made, and then somebody might learn something. But right now, they're skeptical that tornadoes are actually funnel-shaped, and even if they were, they'd be skeptical that we know for sure that the radius of a vortex reveals the pressure gradient inside. I was thinking about starting a parallel thread (which JREF allows) on my new & improved "the sky is blue" theory. That would have kept the most fanatical skeptics tied up for months. Then maybe a greater percentage of the criticisms on my "EHD tornado theory" would be legitimate. Regardless, I have benefited greatly from criticisms on that board, which is why I went back for another serving.

    Quote Originally Posted by Nereid View Post
    To what extent have terrestrial tornadoes been successfully modeled? As in either computer-based simulations (based on boundary conditions and sets of equations), or in scaled-down 'in the lab' simulations (or both).
    The modeling that meteorologists are doing is numeric, not physical. The Sullivan model is perhaps the most complete. It has a downdraft along the centerline, starting at the moderate low pressure in the mesocyclone, and heading for the extreme low pressure at the base of the tornado, whose energy source is the moderate low pressure in the mesocyclone. The downdraft hits the ground with enough force to kick up dust that gets accelerated outward by the high pressure. The low pressure at the base of the vortex pulls air inward, along the ground, where the skin friction is the greatest. The debris cloud from the high pressure collides with air being drawn into the extreme low pressure, and everything shoots upward, toward the low pressure in the mesocyclone. The debris cloud from inside the vortex is lofted a couple hundred meters off the ground, while the surface inflow gets inside the debris cloud without colliding with it (otherwise the debris would be kept to the inside), and continues upward, away from the extreme low pressure, toward the moderate low pressure in the mesocyclone. Any questions?

    The laboratory simulations are just as unrealistic. The ones that produce the most life-like vortexes are closed systems. I presented one strategy in the OP, which uses a vacuum chamber with an inlet in the bottom. That work was done in the 1970s. More recently, researchers have been using a metal shroud to create the bottleneck. (See the "tornado simulator" used by Gallus et al. (2004).) Without mechanically instantiating a bottleneck, vacuum vortexes are not tornado-like.

    By comparison, I'm attempting to identify the realistic forces that could instantiate a bottleneck. The operational significance is that these are the forces that we should be looking at, in order to assess the risk of a real tornado forming, and which could hurt people if it does.

  16. #46
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    Thanks for the clarifications.

    If you were to ask me about internet discussion fora on astrophysics (however defined), I could reel off a half dozen names in a heartbeat, and come up with another half dozen or so soon afterwards. Ones that focus on meteorology? I have no idea.

    Looks like you are approaching this topic appropriately (have done a literature search, become sufficiently familiar with the underlying physics, etc). The scope of this section of BAUT is pretty clear; I cannot see how I can actively participate any further in this thread.

    Suggestion: you might like to consider requesting that your 'mirage' ATM thread be closed. That way you can come back to it at a later time, if you wish.

  17. #47
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    Interesting video of tornadoes making trailers into box kites here
    http://news.nationalgeographic.com/n...-homes-nation/

    Your thread on dust devils made me remember an article I remembered from years ago. There was a cave where folks were warned not to build bonfires. One researcher did anyway, and it spawned a whirl that left the mouth of the cave and grew into a dust devil, if memory serves.

  18. #48
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    There was a long time ago a piece in Scientific Americal about making a tornado at home with two vacuum cleaners blowing, not sucking, basically mounted at right angles. I tried it and it works. Although I have forgotten the details I think there was a heater involved too although that might have been from the cleaners which pump out hot air. (cylinder tyype with hoses)

  19. #49
    Quote Originally Posted by publiusr View Post
    Interesting video of tornadoes making trailers into box kites here...
    The lofting of heavy debris is yet another problem for the standard model. Trailers are "relatively" light, and can be rolled in 50 m/s winds. But the image shows a trailer lofted what looks to be 100 m above the ground. If there was a terminal velocity updraft that somehow got underneath the trailer and picked it up, the trailer achieving such a height would make sense. But outside of the tornado and below the cloud, there isn't any updraft at all. The dust and debris simply rotate slowly around the vortex. The heavier debris fall somewhat faster than the dust, but the trajectories are clearly non-ballistic, and defy an aerodynamic explanation. (Trailers aren't good airfoils, and could only be lofted by terminal velocity updrafts.) IMO, this is evidence of an object that was subjected to triboelectric charging and was then lofted by the electric force.

    Quote Originally Posted by profloater View Post
    There was a long time ago a piece in Scientific American about making a tornado at home with two vacuum cleaners blowing, not sucking, basically mounted at right angles.
    Making a vortex is easy. You can hold a fan 1 m above the floor, pointing upward, and in the other hand hold a piece of cardboard that will deflect the inflow away from a simple radial pattern, and voila, you have a vacuum vortex. But creating a vacuum vortex whose radius is narrowest on the floor (like a tornado) is impossible by this method. The radius will always flare out at the lower boundary.

    Here are examples of open-air vortexes. Note that wide-mouth vortexes emerge out of the turbulence at the lower boundaries, and that the vortexes tighten with proximity to the source of the low pressure.


    Now here are some tornadoes. Note that they are well-organized at the base, and that the radius is tightest on the ground. Above the ground, the vortexes expand in the direction of the flow.


    The difference in the flow fields is summarized in this image. This is the aspect of tornadic vortexes that has never been explained. The significance is that without the concentration of energy at the ground, tornadoes would be nowhere near as destructive. In other words, existing science has a good general understanding of tornadoes, but why they can unleash so much power on the ground remains a mystery. That's like saying that we have a good general understanding of how light bulbs work -- we just don't understand why they're so bright! So figuring out the actual nature of the energy release in a tornado, in mechanistic terms, is the focus of my work.

  20. #50
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    We are still just getting 'look at the pictures'. I don't see any real support or evidence.
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  21. #51
    What would you like for me to support? I failed to convince the folks on the JREF board that tornadoes are funnel-shaped. (Now that's skeptical!) Are you asking me to support that contention?

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    Thanks again for the pictures. Do you,have any simulation or suction vortex pictures where the inflowing air at the ground has rotation. Rotation would cause ever increasing spin and pressure drop at the base , encouraging a higher vortex to reach down from the cloud to touch the ground. In a simple suction vortex you would expect the tightest rotation at the nozzle. But if the ground air has initial angular momentum, you might expect the tight spot at the base> No?

  23. #53
    Quote Originally Posted by profloater View Post
    Do you have any simulation or suction vortex pictures where the inflowing air at the ground has rotation?
    All of the suction vortexes listed in post #49 had rotation at the ground level -- otherwise the vortexes wouldn't have formed. The rotation isn't projecting downward from the source of the low pressure -- it is coming entirely from the angular momentum of the inflow.

    Here's a video of a semi-closed-system vacuum vortex, but you have to look carefully at the set-up to understand what's going on. He creates an artificially high degree of angular momentum by pumping air into the apparatus at the back right corner. Once all of the air in the chamber is already spinning, then he turns on the fan, and all of the angular momentum is condensed into a vortex. So this isn't a steady-state vortex, and without the containment, this degree of angular momentum would not be possible. Also, the inconsistent air-smoke mixture is a somewhat imperfect flow visualization device. The lines of motion flare out at the base, but you have to look carefully at the halo of thin smoke on the outside to get a sense of the actual dimensions of the vortex. The inner core doesn't define the radius of the vortex -- you have to find the distance from the centerline at which the motion is circular (in plan view). In other words, the point at which the centrifugal and centripetal forces have achieved equilibrium defines the radius of the vortex, not the point where the smoke is the thickest.

    "Tornado simulation", courtesy Instructables

    Contraptions like this are commonly used to "simulate" tornadic vortexes, but none have ever achieved a steady-state vortex in an open apparatus where the smallest radius is at the boundary.

    It is certainly true that the greater the angular momentum of the inflow, the more the radius of the vortex is constricted at the entry point. In an open system, large angular momenta are created by extreme velocities as the air responds to an extreme low pressure. But in an open system, the vortex flares out at the base, and the limit of the possible "constriction" stops at the cylindrical form. There is no way to constrict it further, such that the radius is even narrower at the base. In a sub-sonic open flow, the pressure equalizes throughout the vortex. Since vacuum vortexes cannot be supersonic by definition, sub-sonic laws always apply. If the pressure equalizes, minus friction, the lowest pressure in the system will be at the source of the low pressure. Where the pressure is the lowest, the radius will be the tightest. Hence in an open system, a radius that is tightest at the greatest distance from the source of the low pressure is not possible.

  24. #54
    I neglected to mention one other thing that should always be taken into account in atmospheric fluid dynamics. At a small scale, Helmholtz's laws are good predictors of the behaviors of vacuum vortexes (i.e., vortexes project away from the source of the low pressure, until they are truncated at a boundary). But at the scale of a tornado, we have to take the atmosphere's density gradient into account. In the first 1 km above the ground, the density drops by about 15%. This means that if there is a low pressure inside the storm 1 km above the ground that is pulling air inward, that low pressure will have a much easier time pulling air laterally at its own altitude, compared to reaching down to lower altitudes to get air, because the higher air is lighter, and the low pressure doesn't have to hoist air that is 15% heavier from the ground level. For this reason, a vacuum vortex extending into a denser fluid will either flare out long before it hits the boundary, or it will snake around to reach out laterally into the lighter fluid. In other words, the flare in the open-air vortexes at a laboratory scale should be much more dramatic at an atmospheric scale.

    So, if you think that I'm making all of this stuff up, I'm not. Consider the following abstract (with my bolding). Note that "numerical modeling" is not physics-constrained. It's a matter of telling the computer how fast you want the winds to travel, to match the field data. The researcher explicitly states that thermodynamic limits have to be exceeded in order to model tornadic vortexes. What does that tell you?

    Brian H. Fiedler (1994): The thermodynamic speed limit and its violation in axisymmetric numerical simulations of tornado‐like vortices, Atmosphere-Ocean, 32:2, 335-359

    Processes that regulate the central pressure and maximum wind speeds of tornado-like vortices are explored with an axisymmetric numerical model. The model consists of a rotating cylinder of fluid enclosed within rigid boundaries. The momentum diffusivity is a fixed function of height. In the rotating reference frame, relative motion is induced by a buoyancy force in the vicinity of the rotation axis, leading to the formation of a central vortex. The work done by the central buoyancy force on a parcel rising along the axis defines theoretical and empirical wind speed bounds on both the updraft and the low-level vortex. Certain processes are found that allow for the vortex to greatly exceed this wind speed bound, or the so-called thermodynamic speed limit; however, in most of the parameter space the vortex wind speeds are close to the thermodynamic speed limit. The most effective limit-breaking process involves a supercritical end-wall vortex with an axial jet. In steady state, the supercritical vortex sustains wind speeds 2.0 times the speed limit. A transient end-wall vortex, with the vortex breakdown traveling rapidly downwards toward the surface, is able to achieve wind speeds 5.0 times the speed limit. Warming of the subsiding vortex core past the vortex breakdown increases the maximum steady-state azimuthal wind speed by about 20% from what it would be otherwise. Axial momentum diffusion is not found to significantly enhance the surface pressure deficit in any of the simulations.

  25. #55
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    I think there are still a few folks who think that there may be an upward speed that is greater than supposed. Ironically work done on tornadoes may reveal info on jets from black holes or other phenomena.

    JREF didn't concede that funnels are funnel shaped? Perhaps what they mean is that the condensation funnel is--or can be--funnel shaped. I have seen posters of bell shaped tornadoes, invisible funnels (one tore a car from a freeway on KFOR a year or three back...)

    Jarrell seemed to start as a landspout and backed into the city, then grew into a monster when it tapped into a true meso'

    Interesting wind field map (slow to up-load) http://up-ship.com/blog/?p=14296
    Last edited by publiusr; 2012-Apr-09 at 10:24 PM.

  26. #56
    Quote Originally Posted by publiusr View Post
    Ironically work done on tornadoes may reveal info on jets from black holes or other phenomena.
    How would that work?

    Quote Originally Posted by publiusr View Post
    JREF didn't concede that funnels are funnel shaped? Perhaps what they mean is that the condensation funnel is--or can be--funnel shaped. I have seen posters of bell shaped tornadoes, invisible funnels (one tore a car from a freeway on KFOR a year or three back...)
    They were "skeptical" that the tightest radius in a tornado is on the ground. Some tornadoes are funnels, some are wedges, and others tend toward the stovepipe shape, but in all cases, the tightest radius is at the ground. They cited some photography in which it was hard to tell what was happening at the ground, such as when the base of the vortex is invisible, and said that since all tornado photography does not support my "contention", I must be wrong. Where I went to high school, they would have been kicked off the debating team for reasoning like that. Anyway, it didn't surprise me that the discussion went that way. I answered all of their legitimate questions, and then they could see that if they accepted the opening statement, they'd have to accept the rest of it. I took it as a compliment that the only way that they could disagree was to assume an absurd position.

  27. #57
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    That is a very one sided roundup of the thread on JREF if I may say so.

    However what happens on JREF stays on JREF. IF you are making a case on BAUT you make your case here.
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  28. #58
    OK, so what would you like for me to support? Be specific.

  29. #59
    Here's a thought -- we could debate the definition of a tornado. According to the American Meteorological Society, a tornado is "a violently rotating column of air, in contact with the surface, pendant from a cumuliform cloud, and often (but not always) visible as a funnel cloud."

    Therefore, when I state that "the defining characteristic of a tornadic vortex is that the tightest radius is on the ground," I neglect to mention that this characteristic is not always visible. (Oops -- gonna pay dearly for that one!) I also generalize the definition, from "funnel" to "anything that is narrowest at the bottom", which includes other well-known shapes such as wedges, bells, near-stovepipes, and the various forms of vortex breakdown, which the conventional definition does not. My critics are saying that since I'm not using the exact words as found in the AMS glossary, I must be wrong, because paraphrasing an accepted definition forfeits acceptance, and that's tantamount to disproof of the thesis.

    Yet the "definition" of a tornado isn't so precise that paraphrasing it is self-defeating. In fact, the definition is still a matter of debate in the scientific community. Chuck Doswell, the world's foremost authority on tornadoes, makes the following statements.

    There is no definition of a tornado that has been extensively peer-reviewed.

    [...]

    Other than the Glossary definition, all definitions I've seen, including my own, are not peer-reviewed. Hence none have any formal "approval" except the Glossary definition, which I see as seriously flawed.

    A vortex has to meet some threshold intensity at the surface for it to be considered a tornado. However, when we see a debris whirl at the surface, it's not obvious how to go about measuring the wind speeds to see if they meet some wind speed threshold. Lacking a Doppler lidar, the visible evidence of a tight circulation capable of producing a debris cloud at the surface is all we have to go on in ascertaining whether or not a tornado is present.

    [...]

    From my perspective, a tornado is defined (by any reasonable definition), as a vortex. A vortex is a kinematic entity -- a process described completely by the specification of the velocity field as a function of time and space. The dynamics of vortices -- a description of the physical processes that give rise to the vortex -- probably vary considerably from one event to another, and in general are not very thoroughly known. It makes no sense to me to base a vortex classification system on dynamics when those dynamics aren't known definitively and certainly can't be assessed just by looking at the vortex and attendant storm. We're only marginally capable of saying anything about the velocity field, much less the processes that give rise to it. Instead, I'm arguing that we put some essentially arbitrary (but, hopefully, reasonable) thresholds on which vortices we are going to call tornadoes -- as I am doing in this essay -- from a purely kinematic perspective. When and if the dynamics become well-known and can be determined definitively from available observations, then they can and should be the basis for a revision of the classification system.
    I disagree with Dr. Doswell on a couple of points.

    First, he's saying that we cannot reasonably classify tornadoes on the basis of dynamics that we don't understand. While that "sounds" reasonable enough, there's an insidious process at work, and which can lead to bad science. If we define tornadoes in a way that we can't explain, it reveals the fundamental mystery, and that's bad. So let's make sure that we define tornadoes in a way that's consistent with the way that we're going to explain them. Then, we're right by definition, and that's good. I'll refrain from delving into the philosophical issue just below the surface here, but suffice it to say that all people (myself included) always define things in a way that is consistent with the hypothesis that follows -- otherwise, they don't have formal hypotheses. The error is to think that somebody who refines the definition to reveal an aspect that is not currently understood, and which his model can explain, is wrong "by definition." The issue is not whether the hypothesis in question explains the phenomena as currently defined, but rather, as correctly defined. In other words, in definitive proofs, it all comes down to definitions. I'm maintaining that my definition is the most general, as it includes all tornadic forms. My definition is also more specific than AMS's, as it explicitly identifies the essential aspect, that in all (visible) cases, the radius is tightest at the ground (if only by a little bit in stovepipes). This definition makes the rest of it go quickly, as I can demonstrate that in an open system, a vacuum vortex is never like this, while in a closed system, a vacuum vortex is always like this. Once framed as a closed system vacuum vortex, the rest can be derived incontrovertibly. So focusing on the radius of the vortex, and examining the implications thereof, is useful. Doswell's definition basically just states that the wind speeds have to be above a certain level for it to classify as a tornado. This is useful for statistical purposes, and lays the foundation for statistical forecasting. But if it rules out further investigations into the mechanics of tornadoes, which are wrong by definition because meteorologists don't define tornadoes mechanistically, an error has been made.

    As an analogy, there was once a time when people did not understand tsunamis. So they were defined simply as really big waves. But the dynamics of tsunamis are quite distinctive, and are very different from "normal" waves in the ocean. Eventually, scientists figured it out, and now tsunamis are defined differently. They can be big or small, but they are always caused by displacement, which creates a different type of wave. The refined definition enables the explanation of the entire phenomenon. This is what I'm attempting to do for tornadoes. I may be wrong by definition, but that might mean that the definition is wrong.

    Second, having defined tornadoes as wind speeds above a certain threshold, Doswell then states that the "dynamics aren't known definitively and certainly can't be assessed just by looking at the vortex and attendant storm." In other words, tornado photography is static, and doesn't reveal the velocities within the flow field, and therefore, it tells us nothing of the dynamics of the vortexes. This is incorrect. Tornado photography does not tell us the speeds of the air, but it does tell us the pressure, and the extreme low pressure at the ground (which conventional meteorology cannot explain) is the key to the mechanics of the phenomenon. To understand Doswell, we have to understand the context in which he's making statements. Inexplicably, size and speed are only loosely related in tornadoes. Rope tornadoes can do EF5 damage, while huge wedge tornadoes (radius > 1 km) sometimes only do EF2 damage. So meteorologists downplay the form of the tornado, and approach the whole thing from a purely statistical perspective. They don't care whether the tornado was big or small, or whether it was a wedge or a rope. The tornado gets recorded as an EF0~5 depending on damage assessment, and this is used in probabilistic modeling which influences operational forecasting.

    I wouldn't disagree except for the fact that this approach has hit the point of diminishing returns, and many researchers are becoming of the opinion that the reliability of tornado warnings will not improve with the existing strategy. I'm contending that in not collecting EM data for inclusion in the statistical analysis (because they don't understand the significance of these forces), meteorologists are missing the essential ingredient, and that improvements can only be made with a new model that incorporates these factors.

  30. #60
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    If ground conductors are no use (previous reply) then what experiment would you propose to find the EHD effect?

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