Water Hammer Wave Reflection and Valve Closure Time

[@ntuthuko3175]

This is the best teaching I've ever received on transient flows. Thank you!

[@Nirleponshishprapanc]

Mike wonderful, as a Civil engineer and all my life as a Hydropower Construction engineer I kept repeating Water Hammer, but never ever got anyone explaining it mathematically. I am sorry to see so few thums ups for such a masterpiece of an explanation. I will circulate and also share links. Infact my invention JALODBUST is based on this phenomenon, and JALODBUST will change face of humanity. It recently got selected Winner for ASME ISHOW 2020 for Hardware-led social innovation. Let me say, It's not a commercial hit, social has the poor as beneficiaries. I have chucked my job in favor of being worth to the humanity in a small way. Thanks again.

[@lukestube8017]

Hi Mike, Confused as to why the High pressure in the pipeline would rebound from the lower pressure tank at t3 and cause a negative pressure in the pipeline instead of causing the tank to surcharge. This is what we would normally see in a surge tower or hydropneumatic vessel. Could you provide some insight? Cheers Luke

[@prash2541]

hi mike, do you think you might have something for rapid valve closure, as well as pump start and pump stop?

[@赵俊涛-x7q]

Hello ,Mr. Mike ,thanks for sharing the knowledge of water hammer . I'm interested in what happens when there is a branch and a water hammer event.

[@pedroramos3265]

Hell of an explanation. Come on Michael, cant wait for the third one with the branch.

[@Nelson1000]

Mike, have you looked at how these formulas apply to mud pulse telemetry that is used in drilling wells. MWD (measurement while drilling) tools encode data and send it up to the surface by creating a mud pulse wave. I want to understand more about the wave that is created as the orifice is closed and opened to create the pulse.

[@pulsedflowsolutions9058]

Can you explain why the pressure wave is reflected on the open reservoir?

[@prash2541]

and the hammer sound is the velocity of water hitting the valve at 3t. is that right?

[@mengqianlu]

Very clear explanation!

[@drummer_bot8985]

Thank you for the video, as I am not very knowledgable about fluidic mechanics or a hydraulics engineer I have found it very useful. With regards to transient flow, I'm hoping you can help me with a problem I'm having. I'm trying to find information on pressure surge waves generated by microsolenoid valves within microbore flexible tubing, but I'm having a hard time finding any. Is there any literature that you know of that could help? Thanks.

[@saidlhadjdihia3171]

me to i need any literature , can you contatce me to work with me if you went

[@doubleo8260]

Sir it will be helpful if you post video on “how to do CFD analysis on water hammer “

[@rahulkumargarg3224]

I am a research scholar working on water hammer analysis in the pipeline. I want to make a test rig for an experiment showing water hammer phenomena in both for rapid and slow valve closure. my operating pressure is 7 Bar. please advise me how to construct my experimental test rig.

[@rahulkumargarg3224]

sir, how can get damping waves in a example like: a=335m/s, length=240m, initial velocity=.86 m, head=23.10 considering with or without friction factor

[@WladyslawAntonsiewicz9627]

What if we have a variable diameter of the pipe ? ... like for example if there in the middle of the pipeline a distributional tank ?

[@MikeCrowley]

As you increase the diameter the velocity reduces so the surge pressure will be lower in the larger diameter sections

[@WladyslawAntonsiewicz9627]

@@MikeCrowley thank you Mr. Crowley so to calculate this pressure in that section I should run the same equations with different velocity.... is it is correct to use pernolli equation ? I saw your project Crowley Pump I love it

[@WladyslawAntonsiewicz9627]

cool I understand then the wave will not reflect beside the nick. then in case of variable diameter do I use this equation to calculate the High of the surge tank or should modificate it than to be add to this by using I can calculate the Pressure in the surge tank. I remember that pump called ram works on the same equations and keeps compressing until the surge pressure in the pipe equals to the pressure in the compressing chamber.. this could be a good video to do :)

[@syedhusainkhatamisyedkhali3821]

why we use 4 to find the frequency?

[@rizkyfarizanfiqri7920]

before i am very thank full to professor (mike crowley) has posted about water hammer video which very help me cause i am student of mechanical engineering has thesis to analysis of fluid dynamic phenomena concerning on water hammer (creating hydraulic ram pump with harnessing water hammer as main power). But i still confusing about effect of water hammer after it is rising up the pressure causes water having supersonic velocity after the valve closed, my question actually very simple but i still cannot get the answer. "after water having happened, the water's behave always makes reflection cause the valve closed...and how long the reflection of water inside the pipe ?" Hopefully you can reply my question, that is big favorable to me...

[@enzoorciuoli328]

1second rest is absorbed in air reservior no reservior the hammer will break bolts loose or break pipe

[@enzoorciuoli328]

No reflection absorbed in air chamber

[@marwansallouta2101]

Great explanation, highly appreciated, thank you.

[@aldijanazildzic1737]

very educational, thank you

[@theencanador1348]

I heard if increase the size o the pipe it will reduce the water hammer in gravity system like a faucet (tap) is piped in 20mm then increase the pipe for 32mm and just branch off for 20mm to feed the faucet. I work in NY as a plumber for 20 year there houses does not have a water resevoir the water comes with pressure from the street and i have seen old houses pumbing with 12" pipe long with a cap they called is Air Chamber. Nowadays SioxChief from USA makes a water hammer arrestors to install even at laundry machine faucets. Well the home made air chamber works?? I am in Brasil now the plumbing here is terrible to work they just have the basic.

[@MikeCrowley]

If you have a bigger pipe then this will reduce the flow velocity . If you reduce the flow velocity you will reduce the surge pressures. So yes bigger pipes can reduce the surge or water hammer.

[@saidlhadjdihia3171]

if you have documents or articles about this phenomenon plz send them to me

[@HemakaLakmal1990]

Very informative, thanks a lot

[@kaelanveerasamy3969]

awesome stuff

[@aladinabrash7465]

Thank, well explained

[@alymohammed6346]

شكرا جدا