In modeling offshore structures, one needs to account for the forces exerted by the surrounding fluid.

In-depth studies are given in Kinsman (1965), Sarpkaya and Isaacson (1981), Wilson (1984), Chakrabarti

(1987), and Faltinsen (1993). The vibration characteristics of a structure can be significantly altered when

it is surrounded by water. For example, damping by the fluid (or the added mass) lowers the natural

the forces due to the surrounding fluid. The two important sources of fluid motion are ocean waves and

ocean currents.