Semi-analytical solutions for the hydrodynamics of submerged pontoons of finite length

TLDR: In this paper, a semi-analytical solution procedure for the derivation of first-order wave forces, added mass and damping terms is presented for rectangular pontoons which may be floating, submerged or resting on the seabed.

Abstract: A semi-analytical solution procedure for the derivation of first-order wave forces, added mass and damping terms is presented for rectangular pontoons which may be floating, submerged or resting on the seabed. The development is based on a solution matching technique for the scattered and radiated wave potentials and gradients across common boundaries of the subdivided solution domain. The final expressions are true for waves of arbitrary angle of incidence and singularities due to the case of normal incidence are eliminated. The approach is also generalised for the case where the pontoon is a unit of a TLP offshore production system by referring all quantities to a global co-ordinate system. Numerical results are extracted for a number of benchmark problems and compared with independent values where available in the literature. Excellent agreement is obtained for wave forces, added mass and damping values for cases involving floating, submerged and bottom-founded pontoon configurations.