Water hammer is caused by the inertia effect of the flowing fluid being subjected to an abrupt changes in velocity, e.g. when rapidly closing a valve. There is a distinction to be made between rapid pressure changes that propagate with the sound velocity (water hammer) and slow pressure changes caused by mass oscillations.
Hydraulic ram – pumping using water hammer
Formation and effect of water hammer.
Water hammer in pipes
Water hammer as a function of valve closing time; calculation of the wave propagation velocity in water.
Water hammer and surge chamber
Investigation of formation, effect and function.