Talk:Hydraulic analogy

message: This site says: "Many writers eventually resort to some kind of water analogy to try to explain how electricity works. I have yet to see what I thought was a really good water analogy. If you want to explain electricity, talk about electricity. Hydraulics is another field entirely. Avoid this trap; it is already full."
Although I agree that most such analogies are done poorly, the potential exists for a perfectly accurate one, as they are both fluids flowing down conduits.  I hope to make a page for the wikipedia that collects these ideas together into a coherent whole that the naysayers and nitpickers can then edit to perfection. - Omegatron
So I had this in my user space until it evolved into something vaguely encyclopedic, and then merged it with the pre-existing article which was just a table of related equations.  Now that it is in the main article space it should evolve a lot faster. - Omegatron 02:48, July 12, 2005 (UTC)
Already I can see problems because the links are taken from websites that don't appear to be credible. If anything, they appear to be the incoherent jibberings of clueless amateurs. Take for example how pressure is equated with voltage. I'm afraid this doesn't make sense to me since pressure is what moves the liquid and so would be better equated with the electrical field since this moves charge. Secondly, unlike pressure, there is no such thing as voltage existing at a point. Voltage measures the energy gained or lost when charge moves between points and so is always referenced to two points. If you want a hydraulic analogy of voltage, then this will have to be equivalent to the energy lost or gained when a certain volume of water is transferred between two points. i.e. the  change in (KE + PE). —Preceding unsigned comment added by 80.47.114.136 (talk • contribs) 
: You're only half-correct.   Potential (voltage) can be described two ways: joules per coulomb for transporting a test-charge, but Potential also is the line-integral of the e-field.  Because of the latter, electric fields can be described directly in terms of Potential, without referring to energy, as planes (shells) of equipotential.  In other words, voltage is simply a way to describe e-fields.  Volts/meter is fundamental, it's the field, while volts = joules/coulomb comes from the transport of a test-charge *through* a field, a field which is composed of volts/meter values.) 208.38.200.183 (talk) 14:33, 21 April 2014 (UTC)
thread_title:  Goal 

message: I've added a section about the limits of the analogy.  (Useful analogies can lead to serious misconceptions when we don't know when to drop them, and instead use a better model.) — Preceding unsigned comment added by Wjbeaty (talk • contribs) 20:12, 4 April 2006 (UTC)
thread_title:  Failures of the model 

message: although the 3d images are nice, 2d would be much clearer.  —Preceding unsigned comment added by Laplacian (talk • contribs) 02:03, 13 May 2008 (UTC)
replies: text: 2D images might be a little easier to make sense of, perhaps.  I've replaced those low-resolution 3D images I drew sometime back with nicely detailed SVG's, which should eliminate the clarity problem altogether.  Besides, 3D images just look better than 2D. Vanessaezekowitz (talk) 08:49, 22 July 2009 (UTC)
thread_title:  2D would be clearer 

message: Might it be better to describe inductance as a turbine instead, or in addition to, a paddle wheel?  It seems easier to visualize a turbine as part of a closed hydraulic system as opposed to a paddle wheel, which really only works in a hydraulic analogy that includes gravity.  —Preceding unsigned comment added by 128.118.147.10 (talk) 20:26, 30 May 2008 (UTC)
replies: text: I have considered turbines as a model for inductors. Although I have done calculations and found certain models to be mathematically correct, creating a real world physical model of one would be tedious. You see, I reckon that for it to fully represent how an induction coil behaves, it would have to be a turbine such that water can only flow through it if the blades of the turbines move. Also, it would be ideal if the velocity of the blades of the turbine always match that of the water.--Jocajo 22:18, 28 november 2011 (UTC+1)
So I've created this picture of a model for an inductor. It basically already fits the description in the article. Being the quantity that relates applied pressure to acceleration of the current, it can be shown that the inductance of this model equals I/(r*A)², where r is the radius of the middle of the blades to the centre of rotation, A the surface area of the blades and I the wheel's moment of inertia.--Jocajo (talk) 19:32, 8 February 2013 (UTC)

text: Can this work? If water is forced in one pipe would the wheel turn? Adx (talk) 00:05, 18 May 2022 (UTC)

text: I'd better be clearer: The pictured Hydraulic inductor model blocks the flow completely so can't work, so shouldn't really be used as an example in the article. The principle is good, but is physically unrealisable, guessing this was the source of the original poster's question. Adx (talk) 23:27, 8 November 2022 (UTC)

text: As @Adx mentioned, the image you created was good at getting the point across, but it wouldn't have worked. Incoming water would push on both sides of the paddle wheel, making it not turn at all. I replaced it with a rotary vane pump gif and modified the surrounding text to reflect the change. Pgboswell (talk) 20:35, 3 August 2023 (UTC)
replies: text: I don't think a rotary vane PUMP does the job here. A pump adds energy to the system, making the pressure at the outlet higher than that at the inlet. The TURBINE does the job here, as it will dampen high frequency pressure oscillations (due to the inertia of rotating parts) and reduce pressure at the outlet (depending on the load, which should be small in the analogy in order to represent some parasitic resistance in electricity). I love the new animation of the moving vanes (it can represent both a pump and a turbine), but the text saying that a pump would do the analogy seems wrong to me, only a turbine would. Nicolaufg (talk) 09:46, 26 October 2023 (UTC)
replies: text: @Nicolaufg: Actually, an inductor acts as both a turbine and a pump. When it's being energized, it acts like a turbine, but when it's releasing its energy, it acts as a pump. Many types of turbines cannot act as pumps, but the rotary vane pump can act as both a turbine (spinning up when there is an outside force creating a pressure difference across it) and a pump (using its own energy to create a pressure difference across itself). I agree that "pump" isn't the right word to use here, but I'm not sure what a word would be for something that is intended to act as both a pump and a turbine. Any ideas? Pgboswell (talk) 14:11, 26 October 2023 (UTC)
replies: text: @Pgboswell I still believe it is "just" a turbine what best works here. When you explain a pump here, you mention "using its own energy to create a pressure difference across itself". But equipment known as "pumps" in industry, do not use their "own" energy, they get it from a driver through the shaft. On the other hand, it is common to assume that spinning turbines have inertia and thus they will take some time to spin down. While doing that, the energy they transfer to the fluid is NOT coming from the outside (like in pumps), instead, it was stolen from the fluid when the turbine was spinning up, and it has been temporarily stored as rotating kinetic energy (it is indeed "its own energy"). I think I would simply replace the word "pump" and use "turbine" instead. It is already mentioned that it needs to have a heavy rotor, which is what holds the kinetic energy (inertia), and from an industrial equipment point of view (my field), it makes total sense. Nicolaufg (talk) 16:08, 26 October 2023 (UTC)
replies: text: @Nicolaufg: Ok you've convinced me. I think you're right that turbine is a better word. What image should be shown? The rotary vane pump is a pretty simple image to get the point across. I feel like a picture of a turbine is more difficult to understand. Can you keep the same picture, but instead call it a "rotary vane turbine"? Pgboswell (talk) 17:00, 26 October 2023 (UTC)
thread_title:  Inductors 

message: hydraulic analogy (derisively referred to as the drain-pipe theory by Oliver Heaviside)
hard to beleve a scientist/ mathematician would make this statement.refs rq.Wdl1961 (talk) 15:24, 15 April 2010 (UTC)
replies: text: Heaviside wasn't afraid to call them as he saw them. Paul Nahin wrote a biography of Heaviside that outlined his conflicts with just about everyone.  They were a colorful bunch, those 19th century electricians. If I can find my old edition, there may even be that very quotation in it. --Wtshymanski (talk) 21:20, 17 December 2010 (UTC)

text: It needs a reliable source, I've added a citation needed tag.  --George100 (talk) 17:35, 23 December 2013 (UTC)
replies: text:  Found enough of the Nahin book on Google to see that it was Oliver Lodge, not Heaviside, that called it "drain pipe". Found enough of "Electrical Papers" on line to show that Heaviside was a careful user of hydraulical analogies in very specific cases. --Wtshymanski (talk) 15:54, 12 March 2014 (UTC)

text: I have moved it to a separate second para in the article head. It is off-topic to be the first sentence and may be non-NPOV as phrased.  I provided a new first sentence using Mechanical–electrical_analogies as the model, which is terse and to the point.Rick Jelliffe (talk) 03:00, 18 June 2023 (UTC)
thread_title:  drain-pipe theory'  by Oliver Heaviside 

message: The "Hydraulic Analogy" is also the name given to the concept of using water channel flows (through a nozzle) to approximate compressible gas (such as air) channel flows. Basically, it allows you to use a "water tunnel" as a cheap wind tunnel by relating the experimental water flow results to a gas flow.
This should probably have it's own page, but I don't know if I will be able to write it. There should definitely be a link to it on this page. I'll look into it, but someone else might want to give it a try. I've never written a wiki page before.
Some references to get started:
Buchanan, A., Macartney, R., Thompson, M.C., Brocher, E. & Hourigan, K. (2007) Hydraulic Analogy Study of Supersonic Rectangular-Jet Screech Control with Cylinders, AIAA Journal, 45(7), 1539–1545.
http://www.flair.monash.edu.au/publications/pdfs/BucMacThoBroHou2007_aiaaj.pdf
http://www.mubeta.monash.edu.au/publications/content/PIV09-Kumar.pdf
http://www-personal.umich.edu/~mswool/publications/quantitative_flow_visualization.pdf
Water table design for aero research using he hydraulic analogy:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740003970_1974003970.pdf
http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0658669
Crossalchemist (talk) 00:52, 26 August 2010 (UTC)
replies: text: I have added a confuse tag with a link to the Aircraft Flight Dynamics#Analogies section. If anyone can find a better reference in Wikipedia, they might add that as well.  I have also updated the Analogy_(disambiguation) page. Rick Jelliffe (talk) 03:13, 18 June 2023 (UTC)
thread_title:  Hydraulic Analogy - Aerodynamics 

message: It's just occured to me that perhaps the reason properties of lightning are so surprising is the (subconcious or otherwise) attempt to use the hydraulic analogy for electricity - which is particularly misleading when it comes to conceptualizing how lighting travels. Wish I could find a reference for this, because it illustrates a pretty critical limiation of the hydraulic analogy. --Wtshymanski (talk) 21:13, 17 December 2010 (UTC)
replies: text: Lightning is not so surprising if we properly view it as a *change* in conductivity, where insulator (a fluid barrier) is converted into conductor (a circuit path.)  The hydraulic analogy would be the growth of a fracture through a very thick pipe wall, i.e. the solid being converted from a barrier to a passage.  And fractures in solids even display the dendritic branching behavior of lightning.  Of course to be complete, the fracture would have to convert some of the substance of the pipe into a liquid, as if the tip of a growing fracture in a block of ice could produce some meltwater which fills the fracture. 208.38.200.183 (talk) 15:05, 21 April 2014 (UTC)
thread_title: Why [[Lightning]] is so surprising

message: I largely rewrote this paragraph. The possibility of "if a hole is made, the water can pour out" has nothing to do with inapplicability of Kirchhoff's current law (I guessed it was that the original author tried to explain). First of all, the analogy relies on volume (because pressure=energy/volume), not mass or other conserving quantity. An analogy to the Kirchhoff's current law should imply that the volume of the liquid is constant, even locally constant. This is possible with some clauses, but IMHO has little practical importance. First, the liquid must be incompressible. Second, the system should be enclosed in a hard envelope, such that its volume become constant. Third, this volume must be entirely filled with incompressible liquid. Then we may have the Kirchhoff's current law. And this does not mean that there are no leaks. This means that there are no exchange of substances with the outer environment, either by leaks or by moving parts such as pistons. Because this explanation is quite long, I wrote in short, why Kirchhoff's current law does not hold and removed all irrelevant reasonings. Incnis Mrsi (talk) 18:55, 19 February 2012 (UTC)
replies: text: There is no need to say that Kirchhoff's laws hold always in every hydraulic circumstance, or don't. I think the purpose of the article is served by showing just one hydraulic situation in which it holds, so that people can understand why it might be true for circuits. Therefore I put an example in the article with a picture of a copper tee and a description of how water flows equally into and out of it. --Steve (talk) 20:25, 27 April 2012 (UTC)
thread_title:  Leaking pipes 

message: I have the feeling that pneumatics may be a better analogy because acoustics are more pronounced.
Altho the analogy is still flawed, acoustics remind me of how potential travels through electric cirquits. It is usefull for explaining stuff like reflections on signal lines and decoupling capacitors.  — Preceding unsigned comment added by 83.87.238.229 (talk) 16:03, 12 March 2013 (UTC)
thread_title:  Hydraulics vs Pneumatics 

message: After seeing all the complaints about this article, I would like to endorse it.  Analogies are not only useful for understanding electricity, but also for analyzing similar systems (such as sound waves in a muffler).  It is not important which analogy is used, once the reader understands that analogies are possible, it all becomes quite transparent.  I like the way editors have placed alternatives in the talk page, instead of cluttering the main article with an endless list of analogies.  One reason it's hard to find literature that supports analogies is that the concept is a bit "shallow" for publication.  They are useful for an electrical engineer who wishes to dabble with acoustics.  If this dabbling leads to anything publishable, it is easy to translate the analog equations into proper physics equations using conventional variables (e.g,, pressure instead of "pseudovoltage").--guyvan52 (talk) 16:20, 11 March 2014 (UTC)
replies: text: In my effort to reformat, I had to use two galleries because a rather large laptop screen failed to display five images side by side.  I also condensed the discussion of the voltage source/ current source into one section because the previous version went a bit too far into the different types of hydraulic pumps.  Also, I experimented with putting all the images to the right in the conventional way, but the result was a large gap after the prose ended and the images did not line up with the prose.  I am not sure what the best practices for multiple images in situations like this, but if there is a policy I would be happy to implement.--guyvan52 (talk) 15:44, 12 March 2014 (UTC)

text: I do like the article too. I am a Chemical and Process Engineer and now interested in Electronics as a hobby (home automation, simple robotics, etc). My brain works with hydraulics, and I had a bit of a hard time to "intuitively see" the effect of placing a capacitor or an inductor in a line. This article really made it clear to me. Nicolaufg (talk) 09:57, 26 October 2023 (UTC)
thread_title:  I like this article 

message: Is the figure to the left a unnecessary duplicate of the one to the right?--guyvan52 (talk) 22:12, 12 March 2014 (UTC)
thread_title:  Duplicate figure? 

message: Might the opening sentence be a bit misleading?  We could instead find a quote from a promoter rather than a detractor.  Heaviside, Fitzgerald, Hertz and Lodge worked together on and off during 1878-1902 to flesh out JC Maxwell's work.  Lodge developed many mechanical and fluid analogies of currents and fields for use in his electrical lectures.  He originated most of today's hydraulic analogy, building on JC Maxwell's concept of conductors containing a charge-fluid which was incompressible.  For example, see his capacitor analogy, a water-filled sphere divided by a thin rubber membrane (a balloon,)  0. Lodge "Modern views of electricity" p178 London:MacMillan 1889, described in "The Maxwellians", BJ Hunt 1991 Cornell U. Press.  — Preceding unsigned comment added by 208.38.200.183 (talk) 15:19, 21 April 2014 (UTC)
thread_title:  O. Heaviside derision? 

message: Electricity was thought to be a liquid, when was first discovered, and was described as such for years later. Perhaps it is the historical reason behind this analogy, besides the intuition, for understanding the behaviour of something invisible. The same goes for the glossery used for electricity - the word "current" (flow) comes from the analogy to water. Galzigler (talk) 14:47, 23 September 2016 (UTC)
thread_title:  Historical reason 

message: I have the impression this sentence is wrong: "Also, an accelerating electron will drag its neighbors along while attracting them, both because of magnetic forces."
Shouldn't it be: "Also, an accelerating electron will push its neighbors along while repelling them, both because of magnetic forces"? --91.34.131.163 (talk) 18:29, 20 October 2016 (UTC)
replies: text: No, I think that is right.  Two like charges travelling in the same parallel direction will have magnetic fields that cause attraction perpendicular to the direction of travel.  Each moving electron behaves as a small magnetic dipole.  The effect of an accelerating charge starting an acceleration is other nearby charges is the electromagnetic equivalent of linear frame dragging from general relativity and is in the same direction. It would be nice to have a source reference for that though. SpinningSpark 19:15, 20 October 2016 (UTC)
thread_title:  Attracting electrons? 

message: I've have removed the original research warning template, it being 5-years-old and seems not reflective of the current article. If it is really important to you, object below. Nuvigil (talk) 14:40, 13 June 2017 (UTC)
thread_title: Original Research template tag

message: Please bring up to specs, see: MOS:LEAD:
 "The lead serves both as an introduction to the article and as a summary of its most important aspects. <BR> The lead should be able to stand alone as a concise overview of the article. It should define the topic, establish context, explain why the subject is interesting or notable, and summarize the most important points—including any prominent controversies. The emphasis given to material in the lead should roughly reflect its importance to the topic,"
My emphasis.
Further, the lead, in tone, seems destructive to the analogy by starting with derision and warnings. ...Is starting negatively a good way to teach a complex concept?  I think somebody needs to actually try to fully communicate this highly useful heuristic first. Also I don't think the assumption that this is "THE hydrolic analogy" can be supported. There must be hundreds. <BR>  — Preceding unsigned comment added by 2602:306:CFCE:1EE0:E454:D78D:E92F:E1E6 (talk) 05:19, 30 April 2019 (UTC)
replies: text: Changed lede to analogies. Electrical-Mechanical has uses the plural too. Rick Jelliffe (talk) 04:11, 18 June 2023 (UTC)
thread_title:  Lede out of specs. + Tone 

message: Mention what the electronic analogy of a waterfall is. Jidanni (talk) 00:27, 1 March 2020 (UTC)
thread_title:  Add electronic analogy of a waterfall 

message: Mention what would be the hydraulic analogy of a short circuit. Jidanni (talk) 00:45, 1 March 2020 (UTC)
thread_title:  Add the hydraulic analogy of a short circuit 

message: Perhaps go into various lists of hydrology features,
finding ones to add electrical analogies of which to this article.
*Flood, Dam, Confluence, Stream capture, Fluvial processes
*:Category:Hydrology
*:Category:Bodies of water
*:Category:Hydraulic structures
*:Category:Fluvial landforms
Probably some don't have analogies, but probably many do. Jidanni (talk) 06:26, 1 March 2020 (UTC)
thread_title:  Add lots of analogies 

message: It would be better for this article to remove the sloppy and nonsensical statement "Resistance in most electrical conductors is a linear function [maybe the anonymous author meant: "constant"?; 2012]: as current increases, voltage drop increases proportionally (Ohm's Law). Liquid resistance in pipes is not linear with volume, varying as the square of volumetric flow (see Darcy–Weisbach equation)."   In contrast to what the statement suggests, the Darcy-Weisbach equation article says that the resistance is constant for laminar flow. It reduces to the Poiseuille equation. If there are no objections I would like to remove the statement within a few days. Ceinturion (talk) 09:59, 3 April 2021 (UTC)
replies: text: Done Ceinturion (talk) 18:03, 6 April 2021 (UTC)
thread_title:  Darcy-Weisbach equation 

message: People come here looking for the water pipe analogy that most people are familiar with that explains current, voltage, etc. It's not here. The intro implies that it is.
Derwos (talk) 22:36, 3 February 2022 (UTC)
thread_title:  Where is the water pipe analogy ? 

message: Obviously missing are the equations that model phenomenon. The differential equations from linear systems and the equations based on the Naperian constant 'e'.
Inductors, capacitors and filter networks common to electronic engineering circuits, especially direct current (d.c.) circuits are not presented.
The analogy with d.c. circuits is simplest and easiest to understand and use. 166.198.161.67 (talk) 17:52, 13 January 2023 (UTC)
thread_title:  Engineering Equations?