Hydraulic shock, commonly known as water hammer, is a pressure surge that occurs when flowing fluid is forced to stop or change direction suddenly. This rapid momentum change creates a pressure wave that travels through the pipeline system.

Water hammer commonly occurs when a valve closes suddenly, causing shock waves that can lead to noise, vibration, pipe damage, or even rupture in severe cases.

Engineers reduce these effects using:

Surge tanks

Expansion tanks

Accumulators

Blowoff valves

Controlled valve closure rates

The phenomenon is commonly analyzed using the Joukowsky equation or more advanced hydraulic methods such as the Method of Characteristics. (Wikipedia)