Blade pitch control

[ghost]

Hello.

I have a quick question. I am using OrcaFlex+Wind turbine module and ROSCO is utilized for controller.
I use shutdown mode. My problem is that once shutdown mode is operated, it does not go back to operational mode.
Sometimes, due to ramping time, even before 25 m/s, shutdown occurs. Once shutdown occurs, it does not go back to operational mode even if the wind velocity is below 25m/s.

Is it normal?

[nikhar-abbas]

Hi @jinch999,
This is the expected behavior of ROSCO - once it is shutdown, it will be for the remainder of the simulation.

Nikhar

[ghylander]

AFAIK, OrcaFlex does not allow for initial conditions, ie you cannot start a simulation with the turbine in a near-operation state. This could mean that if using shutdown mode, the controller will enter shutdown mode before the turbine actually begins operation.

Can't think of a direct workaround to this

@jinch999, you could try using the OrcaFlex python wrapper to setup a script that waits a certain amount of time before calling the actual ROSCO controller, that way you would avoid the controller detecting shutdown conditions while the simulation ramps up

[nikhar-abbas]

Sorry about the delay here -
Another option is to add some sort of "wait" in the ROSCO source code. This would involve something like putting this line in an if statement like:

IF (LocalVar%Time > 60.0) THEN
    LocalVar%SD  = .TRUE.
END IF

The wait time could be added as an input in the DISCON.IN file if there is enough reason to do so.