FCV operating rule for Transient

This all depends on how the FCV in your system is configured and operated. An FCV in a model is a generic model element. Is yours controlled by a PLC? If so, what kind of speed will it respond? If it's relying on a signal from a SCADA system with a long polling interval, it may not move at all during the course of a transient event.

The operating rule would be similar to that of the Valve Closure example file located at "C:\Program Files (x86)\Bentley\HAMMER\Samples". I will look for an example file and post it if I can locate one.

The key with using an operating rule on an FCV in HAMMER for a transient simulation is to match up the Starting Relative closure in your operating rule with the calculated relative closure seen in the Results section of the FCV properties. This is available in recent versions. See:

Modeling existing valves as Throttle Control Valves in HAMMER

As Tom said, if you are looking to model the operating rule to simulate dynamic throttling of the FCV to meet a flow setpoint, consider if the change will happen fast enough to be of significance during a transient event. If you are modeling a transient resulting from a manual/fast closure of the valve, you can match up the relative closure as mentioned above and use the Operating Rule, or you could model it as a TCV to get a bit more control over specifying the valve characteristics/coefficient.