[HYDRODYN] Cylinder Member crossing free surface

Dear NREL team,

Is the Hydrodyn Morison model suitable for the modelling of cylinder crossing the free surface ? If so, how is calculated the immerged volume of such a cylinder at a given time step and is there any rules to follow for a correct modelling of non-linear hydrostatic effects ?

Thank you for your help,

Best Regards,

Dear Cyril,

As described in the draft HydroDyn User’s Guide and Theory Manual: wind.nrel.gov/nwtc/docs/HydroDyn_Manual.pdf, the substructure buoyancy in the strip-theory (Morison) solution is not recomputed based on the displaced position of the substructure, so no linear or nonlinear hydrostatic restoring effects are included. Instead, the user must enter the 6x6 linear restoring matrix to compensate. See section 6.8.3 for more information.

Best regards,