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Drag Coefficient of MHK Turbine Tower
Dear David,
Could you clarify if tower drag coefficients for submerged MHK Turbine Towers are considered in the tower drag load formulation? Or is the drag coefficient only relevant for tower shadow effect?
In the simulation files and snapshot attached (whereby I attempt to isolate the tower drag loads and disable other effects like tower shadow and turbine rotation), I noticed that the tower base shear & bending moment are the same regardless of the drag coefficient inputted in the tower input file. I’m curious if I have inadvertently set-up the simulation incorrectly.
Thanks & regards,
Andhi
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Hi Andhi,
At the moment, the aerodynamic tower drag isn’t evaluated for “submerged” tower elements. QBlade checks whether a tower element is above MSL and only then applies the aerodynamic drag (based on the wind velocity). I’ve updated this behavior so that hydrodynamic drag (based on the wave and current velocity) is evaluated when a tower element becomes submerged.
In the meantime, until the next release is out, you can use the following workaround:
Define the tower as part of the substructure model and place the transition piece at the top (or bottom) of that tower.
Assign appropriate hydrodynamic Morison drag coefficients to the tower elements in the substructure file.
Best regards,
David
