当流体突然停止或受到to a change in direction, a pressure surge commonly referred to as a water hammer event will occur. The momentum of the fluid abruptly stopping creates a pressure wave that travels through the media within the pipe system.This same principle is also applicable when the flowing medium is steam rather than water. In the case of steam, the pressure surge is known as a steam hammer event. Both water and steam hammer events have the potential to cause catastrophic damage.
Water hammer events are transmitted through the system at the speed of sound as applicable to the fluid-pipe combination (speed of sound varies with the density of the fluid). For water in a steel pipe, this is essentially the speed of sound in water (~4600 ft/s or 1400 m/s which is close to 1 mile/s). With this high transmission velocity, pipe segments are loaded in a highly transient manner causing them to shake. As a consequence, significant dynamic loads can be transmitted to the piping supports as well as the system components, i.e. valves, instrumentation, etc.
