Talk:Water hammer

Article's category
Why is this article in the firefighting category? --Andrew 20:04, Feb 7, 2005 (UTC)
 * I'm not sure... perhaps it has some relevance to fluid flow in fire hoses and fire sprinkler systems? -- FP 12:22, Feb 26, 2005 (UTC)

I'll take it out. --Andrew 08:37, Feb 27, 2005 (UTC)

It's linked from Fire hydrant. Kim Bruning 04:02, 10 January 2006 (UTC)

Edited a lot hope you like it. Joukowsky and rigid column theory could be explained. User:Ike 22:23, 02 April 2007 (UTC)

Other source of water hammer.
I'm not sure where to write it in, but water hammer also happens when heaving long pipes that are full of water. When this happens, there is a brief production of water vapour in a partial vacuum before the hammer. Colinvincent 06:33, 22 March 2007 (UTC)

The sentence in the section Mitigating measures that begins, "Often accidents will occur that could hardly be foreseen (sudden release of air pockets) or are" ends abruptly and doesn't represent a complete thought. A list of mitigating measures against the water hammer effect immediately follows, but the list isn't given any introduction or title. It's almost as though someone cut out some text, but forgot to paste it again. I'm not knowledgeable about water hammers, otherwise I would do the edit myself. Anyone feel up to the task? Fungicord 02:17, 7 May 2007 (UTC)

Explosion in NYC caused by water hammer effect
According to this news report. I don't know enough about the subject to update the article.

The "New York Water Hammer Incident" subsection doesn't really belong here. It should be moved to another article with a link from the "See Also" of this page. Tvh2k 01:32, 19 July 2007 (UTC)

Removed section: New York Water Hammer Incident
Perhaps this section (and other notable water hammers) will be of use when more reliable sources are included. The article above mentions that it's only speculation. Ichibani utc 04:08, 19 July 2007 (UTC)

On July 18th 2007 New York experienced an explosion of an underground steam pipe near Grand Central Terminal venting steam, mud, and debris. It has not been confirmed, but one theory is that the explosion may have been caused by the water hammer effect. The initial explosion is cited by Associated Press writer Adam Goldman to have been "as high as the nearby Chrysler Building".

Replaced kinetic energy equations by Joukowky equation
The magnitude of the Water hammer pulse is proportional to the velocity of the flow. Also, after the pipe is of a certain length the magnitude of the pulse remains the same. So it has little to do with the kinetic energy of the flow. I will elucidate the derivation when I get to a textbook. Donebythesecondlaw (talk) 19:34, 10 April 2008 (UTC)

Dynamic equations
The dynamic equations have a variable d that is not defined--pipe diameter perhaps? And they have a lower case v and an upper case V. I assume those are both velocity and the different case is just a typo?Ccrrccrr (talk) 01:00, 1 February 2009 (UTC)

2009 Sayano-Shushenskaya hydro accident
The article on the 2009 Sayano-Shushenskaya hydro accident makes it pretty clear that water hammer was not the cause. Thus I agree with the deletion of a link to an article about that accident.Ccrrccrr (talk) 03:51, 22 October 2009 (UTC)

less threatening
Under section "Mitigating measures": "Water hammer has caused accidents and fatalities, but is usually less threatening."

Less threatening than what? Setreset (talk) 05:58, 25 May 2010 (UTC)

Sign in Joukowski equation
In the differential form of the Joukowski equation, isn't there a - sign missing? dP/dt ~ -dC/dt (P=pressure; there is a positive pressure surge if the celerity C decreases) —Preceding unsigned comment added by 85.2.221.62 (talk) 16:46, 31 May 2010 (UTC)

water hammer when you OPEN a valve, i.e. faucet?
Could this be put in article? I bet it is more common to most people than water hammer from valve closure. Thanks.-Rich Peterson199.33.32.40 (talk) 20:35, 6 August 2010 (UTC)

Similar effects in Optics
Wondering if there is a similar effect in internal reflectance of quantum plasmon surface resonance and phonon generation?

Possible uses offer better control formulas for cerenkov radiation in dynamic fluids. —Preceding unsigned comment added by 24.87.37.216 (talk) 04:47, 24 December 2010 (UTC) Aditya.m4 (talk) 04:44, 24 December 2010 (UTC)

Transport of barometers
Since a Mercury barometer is a column of dense liquid in a glass tube, with near-vacuum at the closed end, great care must be taken when moving one. Air would compress elastically to absorb some of the energy, but vacuum does not. Relevant ? --195.137.93.171 (talk) 08:32, 24 July 2012 (UTC)

Water hammer from a jet of water
This section was added by Uruiamme, removed by Ccrrccrr, and then reverted by Uruiamme:


 * If a stream of high pressure water impinges on a surface, water hammer can quickly erode and destroy it. In the 2009 Sayano–Shushenskaya hydroelectric power station accident, the lid to a 640 MW turbine was ejected upwards, hitting the ceiling above. During the accident, the rotor was seen flying through the air, still spinning, about 3 meters above the floor. Unrestrained, 256 m3 per second of water began to spray over all of the generator hall. The geyser caused the structural failure of steel ceiling joists, precipitating a roof collapse around the failed turbine.

I agree with the removal, so I removed it again.

The citations only mentioned waterhammer once, and that was one of several speculations about the cause of the failure. There was plenty of documentation about the turbine being shut down for excess vibration (4X beyond safe zone) and being operated outside of its design region. Most of the bolts holding down the lid were fatigue failures. The roof collapse is a force issue rather than a water hammer issue; the roof was not designed to withstand the waterjet.

Glrx (talk) 21:45, 13 August 2012 (UTC)

Water hammer used to heat water?
There's a company in Ohio, US IIRC that uses cylinders of metal with laterally incised openings cut in it in linear rows along it's length that is inserted into a chamber of pipe only a centimeter or so larger than the device and is spun up by a small motor as water is flooded into the chamber's gap between the internal rotor and the outer wall. This causes an artificial water hammer effect which, like actual water hammer, causes a massive increase in water temperature. I am surprised that the temp gain of water hammer isn't mentioned here as it's very notable, and this interesting use of water hammer to heat water is even more so notable, even if it were simply because one of the leading companies who make these machines claim they're an over-unity output device (albeit unsubstantiated), it's a very cool and very novel use of a natural event. These devices don't just heat water, they gassify the water and turn it into hot steam in a matter of seconds. Google-fu if this is your forte and expand this article. I know very little about it besides having just learned the ins and outs of this machine due to it's application within the realm of physics and thus feel I am not invested enough in this affect to expand the article or know my way around this article at all. So I hope this gives you some feedback and some ideas for further expansion. BaSH PR0MPT (talk) 13:53, 11 March 2013 (UTC)

Noisy pipes - many causes
People come to this article to learn about noisy plumbing. There are many possible causes and solutions. This article should discuss the subject much more broadly, and/or include useful links to other relevant articles.-71.174.181.102 (talk) 22:28, 7 September 2013 (UTC)

Bulk modulus approximation needs clarification
I think the simplification of the equivalent bulk modulus B=tE/D applies only to pipes with a modulus close to that of water, for example PVC. It may not apply to steel pipe which has a E~=2e11. W ith D/t~=10, K_water~=2e9, the term K_water*D/(Et)<<1, which yields B->K_water instead of B->tE/D. Please correct me if I am wrong. Thanks. — Preceding unsigned comment added by 208.87.239.180 (talk • contribs) 01:04, 3 February 2017 (UTC)