关键词: 振动与波, 钢悬链线立管, 流体流速, 张力, 弯曲刚度, 固有频率

Abstract: Generally, there is high-pressure oil or gas inside the ocean riser. The velocity of the fluid will greatly influence the vibration response of the riser. In this paper, the affect of fluid velocity in the riser on the natural frequency of steel catenary riser (SCR) structure is studied. The results show that the natural frequency decreases with the increase of fluid flow velocity. Thus, one should pay sufficient attention to this phenomenon in the design. Furthermore, the tensile variation of the SCR with the depth is calculated and analyzed. Considering the variation of the tension, the natural frequencies of the SCR is calculated. The influence of bending stiffness of the SCR on the natural frequency of the riser is analyzed. The results show that bending stiffness has little effect on the first 10-order frequencies. Therefore, it can be ignored in calculating the low-frequency mode vortex-induced vibration.

Key words: vibration and wave, steel catenary riser, fluid flow velocity, tension, bending stiffness, natural frequency