Estimation method of viscous forces acting on floating offshore structures

This paper deals with the method of estimating of the viscous forces acting on various kinds of offshore structures. Most of these are blunt-shaped element structures such as a column, a lower-hull and bracing. If we knew the basic data of hydrodynamic forces for such simple element structures, it would be possible to estimate the total hydrodynamic force using those data In this paper we show how to combine basic data to estimate the total force considering the Reynolds number effect, three dimensional effect, and mutual interaction effect of each element. The developed method has been validated by comparing it with model experiments of three kinds of structures, TLP type, column footing type and semi-submersible type structure. Moreover, the applicability of this technique to the full-scale structure has been verified in a field experiment on a prototype offshore structure actually moored in the sea.