Numerical Simulation Of Fluid-Structural Interaction For Vortex-Induced Vibration Of Marine Risers And Attached Fairings

With energy crisis and the depletion of oil resources on land,the exploitation of ocean oil and gas becomes an inexorable trend. Because marine riser is a key protection device of offshore oil and gas exploitation,it has far-reaching significance in the research of the vortex-induced vibration of marine riser to protect the exploit of offshore oil and gas.In this paper, a summary of dynamic response of vortex-induced vibration has been made base on the related phenomena of vortex-induced vibration. And by embedding the code of solving dynamic response equation into fluid solving software , the fluid-structure interaction(FSI)and the solution of small mass rate and low damping vortex-induced vibration of riser have been achieved to get the pressure,vibration amplitude and vortex shedding features. By comparing of present results and the results of classic experiment and other simulations, it shows that the method of this paper has enough accuracy and reliability.Then a series of simulations of different mass ratios and damping ratios have been carried out and find that with the increase of mass ratio and damping ratio , the vortex-induced vibration becoming weaker and weaker with the drag and lift force and vibration amplitude becoming smaller and smaller.At last the FSI method is extended to the simulation of vortex-induced vibration of risers with suppression device fairing to achieve the simulation of vortex-induced vibration of risers with different angles. A conclusion is drown that with the decrease of fairing angles , the intensity of vortex-induced vibration become weaker and weaker and the vibration amplitude become smaller and smaller by comparing the results of different fairings. As a result of this ,the 45°fairing is the best one to suppress vortex-induced vibration. But taking the fairing size into account , this paper take the angle 60°fairing as the best one.