| Marine risers are the main connecter between a platform and the mouth of a well in the seabed. This paper mainly focuses on the Vortex-Induced Vibration (VIV.) of marine risers conveying fluid. The generating mechanism, as well as properties and related parameters of VIV are expressed; Marteoluca wake oscillator model is detailedly analyzed. The partial differential equation for the response of a marine riser considering the effect of the internal flowing fluid and the external marine environmental condition is derived. Then the formula for dynamic characteristics of the marine riser conveying fluid is obtained by Galerkin Method. After the coupled equations of the partial differential equation for the response of the marine riser and the wake oscillator equation are unbounded and discretized by Hermit interpolation function, the Finite Element expression can be obtained and solved by Newmark time-procedure method. The fatigue life of the marine riser is analyzed by Miner's theory and its express is derived; some methods for improving the fatigue life of marine risers are put forward. Through the programming and concrete examples, the effect of the internal fluid flowing on the dynamic characteristics, response of VIV. as well as the fatigue life of the marine riser is analyzed. The results show that the natural frequency of the marine riser will decrease as the velocity of the internal fluid increases; 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. will increase and the fatigue life of the riser will decrease greatly. The top tension can be increased to reduce the effect of the internal flowing fluid on the natural frequency, making the response of the VIV. not too sensitive to the change of the internal velocity and improving the fatigue life, but the stress of the riser will increase correspondingly.
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