Numerical Simulation On Vortex-Induced Vibration Of Marine Riser

Energy industries have paid more and more attention to deep-ocean, with current global energy situation becoming serious. Marine riser is essential equipment for protecting ocean standpipe system. Due to the complexity of the marine environmental conditions, Vortex Induced Vibration (VIV) of marine riser is an important issue for its properly working and safety. Researchers at home and abroad have made some accomplishment on the theoretical and experimental study of riser VIV; but there is much work needed to do about the solution and devices of controlling the VIV of marine riser, and VIV-controlling equipment working practically and reliably has been even rare so far, especially in the domestic.Therefore, this dissertation's findings have important reference value for theoretical research and engineering practice.On the basis of the available research results, this paper, using numerical simulation methods, explored ways by installing additional devices to control the riser's VIV. The optimal VIV control device structure was obtained by analyzing the effect of VIV control device of different structure types on riser.The main tasks are as follows:1. Established mathematics and mechanics numerical model for riser VIV.2. Introduced the mechanism of riser VIV; analyzed the factors affecting riser VIV.3. Stimulated bare riser flow and analyzed hydrodynamic characteristics and force, discussed frequency domain characteristics of VIV, and compared with classical experimental results, confirmed the conclusions of this paper of good agreement with them to establish the benchmark for comparing with the effect of different VIV controlling structures.4. Stimulated the flow field of risers installing different VIV controlling structure (including splitter plates or fairings), and analyzed their influence on flow field, force and vortex shedding frequency of riser.5. Compared the results of different VIV controlling structures modifying riser VIV, especially the effects on force and vortex shedding frequency of riser; then obtained the optimal VIV controlling structures and its geometric size.