A New Interpolation Method for FPSO Motion and Wave Drift Load Transfer Functions

A new method of direction-wise interpolation is proposed. Its merits are first presented by considering the interpolation of 1st order motion Response Amplitude Operators (RAOs) and 3D (ω1 , ω2 , θ) wave drift load Quadratic Transfer Functions (QTFs). In a recent publication (see Ref. [1]), the importance of wave spreading on the spectral density of wave drift loads for a standard storage capacity LNG Carrier (135,000m3 ) in shallow water has been demonstrated. The computation of above-mentioned spectral densities requires the precalculation of a large number of 4D (ω1 , ω2 , θ1 , θ2 ) wave drift load QTF and interpolations between the calculated directions. Application of the new method is investigated in this more challenging context. Examples are selected in the buoyant LNG floating system area with an LNG Carrier in shallow water and an FLNG in deep water.Copyright © 2011 by ASME