What is Water Hammer? – Technology OrgTechnology Org
It is not the name of a superhero. But it packs a lot of physical force inside.
Hydraulic transients – this is the scientific name for this effect. In practice it is also known under the name of water hammer. In fact, you have probably observed it yourself, too. As the name suggests, water is the medium that causes this physical phenomenon, and its action takes place inside pipes, even those that are used for a domestic water supply.
When water flows freely, it gains momentum. When the flow is suddenly stopped, all this accumulated kinetic energy has to dissipate somewhere. For example, try fully opening and then quickly closing your bathroom faucet: did you hear some noise inside? So now try to imagine, what could happen when a water flow is suddenly cut off in a pipe line that is hundred kilometers long.
The following video explains why does water hammer occur, and what are the ways to avoid this effect: