상부 장력 라이저의 시간영역 와유기 진동해석

Abstract

In this study, the time-domain vortex vibration analysis code for top-tensioned riser was developed using the vortex synchronization model of Thorsen et al. (2014). In order to simulate the riser responses induced the cross-flow lift force, the two dimensional lumped mass line model was used. The equations of motion for top-tensioned riser is derived applying the nodal forces consisting of tension, shear force calculated from bending moment and hydrodynamic forces induced from the vortex. Time integration method used the Runge-Kutta 4th order method which is stable and accurate. In order to validate the vortex synchronization model, forced excitation and free vibration simulations of the circular cylinders were performed and compared with the numerical results of the model test. Finally, the response of top-tension riser in the shear current environment was simulated using developed code and compared with the model test.