What is a pressure surge or wave caused by a fluid in motion being forced to stop or change direction suddenly called?

A pressure surge or wave that occurs when a fluid in motion is suddenly forced to stop or change direction is referred to as water hammer. This phenomenon arises when the kinetic energy of the moving fluid is abruptly converted to pressure energy. When a valve closes suddenly or a pump stops quickly, the resultant change in momentum generates a shock wave that travels through the fluid-filled piping system. This can lead to significant pressure spikes that can damage piping systems and equipment if not properly managed.

Water hammer is a critical consideration in hydraulic systems, as the effects can cause noise, vibration, and even physical damage to pipes, fittings, and other components. Engineers commonly implement strategies such as installing air chambers or surge tanks to mitigate the effects of water hammer and protect the system from potential failure. Understanding this concept is crucial for designing safe and efficient hydraulic systems.