Analysis Of Wave Forces On Static Offshore Structures

A thorough understanding of the interaction of waves with offshore structures has been a vital factor in the safe and economical design of offshore structures. There has been a corresponding increase in research efforts to meet this end, but results are widely scattered throughout literature.This paper is intended to study wave forces on offshore structures. Two aspects are going to be discussed in the paper: slender bodies and huge offshore structures. The calculation of wave loads on slender bodies is carried out according to Morison's equation, Linear, Stokes and Cnoidal wave theories. Morison equation suggests that the force acting on a section of a pile due to wave motion is made up of two components: a drag force, analogous to the drag on a body subjected to a steady flow of a real fluid associated with wake formation behind the body. With the help of the computer programs, wave forces on several slender bodies are added up. Besides, some diagrams will be presented to illustrate the relationship between pressure and period, and correlation between pressure and phase. The following study is aimed to give a general of the wave forces on a number of piles. Based on the research of the foece on the slender bodies,a recurrent algorithm for the wave forces on a number of piles is established.A curve will be shown to give the comparamation between the results of the calculation of the program and the results of the experiments.When the body is relatively large, the incident wave train itself being altered by the body, and an alternative formulation is required. However, since flow separation is now usually unimportant, a theoretical approach may be used in which the governing equations of the flow are solved to a first approximation, bearing in mind the additional boundary conditions introduced by the presence of the body. The study on huge offshore structures is undertaken through Bessel equation for vertical circular cylinder and the facet method for bodies of arbitrary geometry to get ΦS (scattered wave components). Finally, a comparison is made between the results obtained from both methods.