Applies To Product(s): Bentley HAMMER Version(s): 08.11.XX.XX Environment: N/A Area: Original Author: Mark Pachlhofer, Bentley Technical Support Group Problem Modeling a valve opening in HAMMER Solution To model this start the valve as initially open by setting the "Status(Initial)" property to 'Active' and set the Headloss Coefficient, discharge coefficient, valve characteristics curve, pressure, flow setting, or hydraulic grade appropriately (what is set depending on the value type and information that you have). Next slowly close the valve with the pattern in order to try to induce as little transient as possible. To do this set the "Transient Analysis Behavior" to 'Valve' then click the option in the Transient analysis behavior dropdown. This will open the patterns manager where you will create an Operational (Transient, Valve) pattern. The 'Starting Relative Closure' of the pattern should be set to 0%. In order to close the valve slowly over a period of time with a pattern you might start the valve closure at 10 seconds and then have it close over a period of 60 seconds as shown below: After you're done you would click "Close' at the bottom of the Patterns manager then select the new pattern that you created in the cell next to the 'Operating Rule' property. Now run the model and check the results in the transient results viewer to make sure the transient has fully settled. If you need to adjust your pattern to elminiate the transient wave you should do that now. We also have information that might be useful for determining the exact time period you need to close a valve in to eliminate or reduce you transient wave under the "Wave Propagation and Characteristic Time " help document found within the software.
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