Research On Vibro-Acoustics Character Caculation For Ocean Engineering Structure

Based on the existing research method, it is difficult to implement shipping vibro-acoustics analysis of large-scaled and complicated container ship. So the modeling method for the numerical computation of vibration and noise distribution on the large container ship in high frequency domain is studied. Statistical energy analysis (SEA) method becomes the dominant choice for analysis of vibration and noise on container ship because of the special structure characters such as large scale size on structure, large hatch width and lower torsion rigidity.Furthermore, the influence of the modeling of containers and the loading conditions on the vibration and noise distribution must be considered during computation. The feasible domain of SEA method on container ship is identified by presentation of the modal density of subsystems in SEA model. The computational results showed the transmission mechanism of vibration and air-borne noise distribution in cabins and structures. And in the middle and high frequency domain, the model of a superstructure from a 10000 TEU container ship is built up for statistical energy analysis.With the increased interest in worldwide deep-water petroleum production, more efforts were put on the research activities on vortex-induced vibrations (VIV) during the past ten years. Despite much progress made both numerically and experimentally, it cannot be stated that a full understanding of VIV problem was achieved. The introduction of steel caternary risers (SCR) has presented new challenges for prediction and suppression of VIV. Therefore, VIV of deepwater risers will remain as one of the most extensive research topics of ocean engineering in the coming years. In this paper, the background and introduction of vortex-induced vibrations of marine risers is presented, which is followed by an overview of the research and progress concerning deepwater riser vortex-induced vibrations, including evaluation of existing VIV analysis tools, numerical methods and experiments together with data analysis and review. More attention is paid to the contribution made by the improving computational fluid dynamics (CFD) method. Conclusions and recommendations for future directions are addressed in the end.