Study On The Responses Of Vortex-Induced Vibration Of Submarine Pipelines And Experimentation

Submarine pipelines are the main components of oil transportation and make the marine oil field contact closely. This paper mainly focuses on the responses of Vortex-Induced Vibration(VIV) of submarine pipelines. The generating mechanism, as well as properties and related parameters of VIV are expressed. Some wake oscillator models are detailedly analyzed. The formula for dynamic characteristics of the submarine pipelines is simplified by wake coupling method and liquid added mass, liquid added damping, liquid added rigidity are obtained. Then the problem is analyzed by general finite element modeling (FEM) software—ANSYS. This paper also introduces some general softwares applied to design and construct submarine pipelines. The experiment on the responses of vortex-induced vibration of submarine pipelines is given. The results of experiment indicate that the allowable span length of the submarine pipelines decreases with an increment in the velocity of internal flow, compression and pressure, increases with an increment in tension. The natural frequency of the submarine pipelines connected by hinge is obviously lower than the natural frequency of those fixed. When the change of the internal velocity leads to the natural frequency of the riser near to the vortex shedding frequency, the response of the VIV increases and the fatigue life of the riser decreases greatly. The top tension can be increased to reduce the effect of the internal flowing fluid on the natural frequency.