Initial surge when using turbine load acceptance operating case

Product(s): Bentley Hammer
Version(s): 08.11.
Area: Modeling


Why do I get an initial surge (apparent surge occurring when there should be not) when using the load acceptance turbine operating case in Bentley HAMMER? What is the proper way of modeling a load acceptance turbine case?


At the beginning of the transient simulation, the turbine is expecting no flow in the upstream pipe for a load acceptance case. This is because the wicket gate is assumed to be fully closed and is only starting to open (and let water in) at the start of the transient simulation.

If you compute initial conditions and flow occurs through the turbine, the transient simulation will not work correctly. To configure the turbine to be initially closed, simply select "Closed" for the "Status (Initial)" attribute in the turbine properties.

Note that this option does not exist in the older version of HAMMER, like build 08.09.400.34. With this version, compute initial conditions and notice that the flow is zero through the turbine. You can now compute your transient simulation (as long as the other turbine parameters are correct.)

See Also

Using Turbines in Bentley HAMMER

Initial turbine HGL the same as the final HGL after load acceptance