Abstract
This dissertation describes the linearized and nonlinear motion response of the riser to regular waves without current and regular waves with current. The linearized frequency domain technique and non-linear time domain analysis are discussed and compared. The finite element method is used for performing dynamic analysis of a two dimensional riser structure subjected to forces generated by wave and current. For dynamic analysis, time histories of the displacements are generated through mode superposition technique. The wave forces in the inline direction (direction of the wave) at any point on the riser are calculated using Morison's equation. Water particle velocities and accelerations are calculated using Airy wave theory. The structure velocity is included in the hydrodynamic drag term. The wave, current, and riser motions are taken to occur in the same plane. Hydrodynamic forces involves only the horizontal components of the current and wave particle velocities. For the frequency domain analysis an improved linearization technique is developed and applied to the hydrodynamic drag term. Accuracy, advantageous, disadvantageous, applications and limitations of this technique are discussed.
Ertas, Atil (1984). A finite element method of riser frequency domain analysis. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -589410.