• InfoWorks WS Pro

Understanding hydraulic transients

Define hydraulic transients in InfoWorks WS Pro models.

Step-by-step guide

Hydraulic transients (also known as water hammer or surge) are pressure fluctuations caused by a change in fluid velocity.

A presentation slide defines hydraulic transients and how pipe material can affect the kinetic energy of flow, where soft materials tend to weaken energy, while stiff materials increase it.

The magnitude of the event is directly proportional to the change in inertia of the flowing fluid.

A presentation slide summarizes how the magnitude of a wave can affect pipes, potentially shortening their lifespan.

Any event that causes the velocity of the water in a network to increase or decrease rapidly can cause a pressure surge or a water hammer.

A presentation slide states that the most common sources of surge events are pump stations and valves, and it displays a graph of a pump transient.

InfoWorks TS, or Transient System, uses the Wave Characteristic Method and calculates the results at the nodes within the network. The method of characteristics requires calculations at equally spaced interior points in a pipeline.

The objective in transient control is to reduce the magnitude (and if possible, the frequency) of the pressure disturbance.

A presentation slide summarizes the objective of transient control to reduce magnitude by slowly closing valves and slowly starting and stopping pumps.