Force due to water hammer (Slow valve closure)

Description

Water hammer (or, more generally, fluid hammer) is a pressure surge or wave caused when a fluid (usually a liquid but sometimes also a gas) in motion is forced to stop or change direction suddenly (momentum change). A water hammer commonly occurs when a valve closes suddenly at an end of a pipeline system, and a pressure wave propagates in the pipe. It is also called hydraulic shock. When the valve is closed slowly compared to the transit time for a pressure wave to travel the length of the pipe, the elasticity can be neglected.

Related formulas

Variables

FForce due to slow valve closure (N)
ρDensity of the fluid (kg*m-3)
LPipe length (m)
APipe cross section (m2)
δvChange in the fluid's velocity (m/s)
δtValve closure time (s)