Boat impact / Point Loading

Wind & Water Computer-Aided Engineering Software Tools
1

Hi there,

i try to figure out how to incorperate a boat impact load case for an offshore wind turbine.

i) is there any possibility to include a single force dependent on time at water line?

ii) If no, would it be feasible to misuse icedyn or icefloe in order to include such a force?

Thank you and best regards,

Simon

2

Dear Simon,

To simulate boat-impact loads or a user-specified time-dependent force at the water line in FAST / OpenFAST will require a small customization of the source code. I wouldn’t bother with trying to use IceDyn or IceFloe for this. For example, you could modify SUBROUTINE HydroDyn.f90/HydroDyn_CalcOutput() so that you add a force to the existing additional platform load i.e. change:

m%F_PtfmAdd = p%AddF0 - matmul(p%AddCLin, q) - matmul(p%AddBLin, qdot) - matmul(p%AddBQuad, qdotsq)

to

m%F_PtfmAdd = p%AddF0 - matmul(p%AddCLin, q) - matmul(p%AddBLin, qdot) - matmul(p%AddBQuad, qdotsq) + XXX

where XXX is your user-specified time-dependent function in six DOF (3 forces, 3 moments, as a vector).

Best regards,