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Initial offset of turbine position
Hello,
I am trying to run a simulation with an initial offset of the turbine, that remains for the rest of the simulation, using the Python interface, but I am running into troubles.
When I use this function setTurbinePosition_at_num(double x, double y, double z, double rotx, double roty, double rotz, int num = 0) before initializeSimulation() the simulation the turbine position is not set at the prescribed position.
If I use the setTurbinePosition_at_num function inside my simulation loop the turbine tower bottom position swifts abruptly and I get in trouble with the structural solver.
Thanks,
João Muralha
Hi João,
the setTurbinePosition_at_num() function is intended to “move” a turbine dynamically during a simulation. As you have observed, if the movements are too abrupt, this can cause the structural dynamics simulation to diverge.
If you simply want to apply a constant offset to a turbine you can directly do this in the simulation dialog (or in the .sim file). I have marked the dialog section in the attached screenshot. The variable names in the simfile are listed below:
GLOBPOS_X – the global x-position of the turbine [m]
GLOBPOS_Y – the global y-position of the turbine [m]
GLOBPOS_Z – the global z-position of the turbine [m]
GLOBROT_X – the global x-rotation of the turbine [deg]
GLOBROT_Y – the global y-rotation of the turbine [deg]
GLOBROT_Z – the global z-rotation of the turbine [deg]
BR,
David
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Hello,
Thanks for the answer. The documentation should be updated then for function setTurbinePosition_at_num() it states:
“This function sets the turbine tower bottom x, y and z position [m], and xrot, yrot zrot rotation [deg]. It can be called before initializeSimulation() if the turbine position should be offset initially or during the simulation loop if it should be changed dynamically, for example during cosimulation with a hydrodynamics software that models the floater.”
Best regards,
João Muralha
Hi João Muralha,
you are correct: This part”…It can be called before initializeSimulation() if the turbine position should be offset initially” is currently broken. Incorrectly, during the initializeSimulation() call, the turbine position is reset to zero. Consequently, calling the setTurbinePosition_at_num() function during the first timestep in the SIL loop, with a large offest from zero, causes the turbine to “jump” instantaneously to the requested position, resulting in the structural model diverging.
This is fixed now in the code and the changes will be incorporated in the next minor release update.
Thanks for letting me know!
BR,
David
