...C. Shi; L. Manuel; M. A. Tognarelli; T. Botros This study is concerned with vortex-induced vibration (VIV) of deepwater marine risers. Riser response measurements from model tests on a densely instrumented long, flexible riser in uniform and sheared currents offer an almost ideal setup for our work...

... that the primary response of the structure would be in its fundamental mode of vibration. In order to glean a greater physical understanding of the ice-structure interaction phenomena, it was critical that this study set out to develop a multimode forced response for the pier when a moving ice floe makes contact...

...Raed K. Lubbad; Sveinung Løset; Geir Moe Vortex induced vibrations (VIVs) may cause a large amount of damage to deep water risers. Helical strakes are used as a mitigating measure to suppress these vibrations. The purpose of this paper is to verify the efficiency of round-sectioned helical strakes...

...Gautam Chaudhury A new model for fluid structure interaction during vortex shedding process and associated vortex induced vibration (VIV) of a cylinder in transverse direction is proposed. The present work is based on restrained inline motion. Nevertheless, the model can be further extended...

...Hongxiang Xue; Jinting Guo; Wenyong Tang; Shengkun Zhang In this study, a simplified empirical model for fatigue analysis of top-tensioned risers due to vortex-induced vibration (VIV) in a nonuniform current is presented. Compared with previous studies on this subject, this model is able to take...

...Per M. Josefsson; Charles Dalton The transverse vibratory response of a long, slender vertical top tension riser, subject to an ocean current, is studied. The problem is treated as a coupled fluid flow/vibration problem, which is solved numerically. The fluid flow part is represented by the 2D...

...Kevin Huang; Hamn-Ching Chen; Chia-Rong Chen Recently, some riser vortex-induced vibrations (VIVs) experimental data have been made publicly available (oe.mit.edu/VIV/) including a 10 m riser VIV experiment performed by Marintek, Trondheim, Norway, and donated by ExxonMobil URC, Houston, TX, USA...

.... The offsetting effects of gravity and buoyancy are included in the analysis. These forces can provide considerable axial loading (as can thermal changes), and hence, stability (buckling) is a major concern. Initial studies are based on the planar problem. A free-vibration analysis is also conducted for small...

... surface erosion, noise, and structural vibration. For both wind and tidal turbines, the flow field may vary temporally and spatially based on boundary layer variations, random gusts and currents, and interaction with topography/bathymetry. Tidal turbines also need to be adjusted for periodic bidirectional...

... approaches involved in life-cycle cost evaluation, such as the global reliability under the extreme ice load, the dynamic reliability, and fatigue life induced by ice vibration, are studied. The proposed life-cycle optimum design formulas are applied to a typical ice-resistant platform in Bohai Bay...

...K. Raghavan, Ph.D.; Michael M. Bernitsas, Ph.D.; D. E. Maroulis, Graduate Student The concept of extracting energy from ocean/river currents using vortex induced vibration was introduced at the OMAE2006 Conference. The vortex induced vibration aquatic clean energy (VIVACE) converter, implementing...

... of vortex-induced vibration (VIV) of a drilling riser located at a 1000 m water depth site. Proper orthogonal decomposition (POD), an efficient numerical technique for characterizing the spatial coherence in a random field, is employed here to identify energetic current profiles. The accuracy resulting from...

...Guojun Huang; Pengfei Liu A dynamic model for the ice-induced vibration (IIV) of structures is developed in the present study. Ice properties have been taken into account, such as the discrete failure, the dependence of the crushing strength on the ice velocity, and the randomness of ice failure...

...Michael M. Bernitsas; Y. Ben-Simon; Kamaldev Raghavan; E. M. H. Garcia The vortex induced vibrations for aquatic clean energy (VIVACE) converter is a new concept to generate clean and renewable energy from fluid flows such as those abundant in oceans, rivers, or other water resources...

...A. K. Banik; T. K. Datta The vortex-induced oscillation of TLP tether is investigated in the vicinity of lock-in condition. The vortex shedding is caused purely due to current, which may vary across the depth of the sea. The vibration of TLP is modeled as a SDOF problem by assuming that the first...

..., and have a 10 – 20 year life. The vortex induced vibration aquatic clean energy (VIVACE) converter—invented by Bernitsas and Raghavan, patent pending through the University of Michigan—satisfies those criteria. It converts ocean/river current hydrokinetic energy to a usable form of energy...

..., including frequency domain approaches. A good understanding of the intricate coupling mechanisms is paramount for making appropriate approximations in an efficient method. To this end, a simplified two degree-of-freedom system representing the surge motion of a vessel and the fundamental vibration mode...

... of the number of modes of vibration is studied, as is the influence of the mass ratio and the value of the damping coefficient. The flow past the riser is represented by a shear flow, ranging from Re = 8000 at the lower end of the riser to Re = 10,000 at the upper end of the riser. The riser vibration...

...Ioannis K. Chatjigeorgiou The present work treats the bending vibration problem for vertical slender structures assuming clamped connections at the ends. The final goal is the solution of the associated eigenvalue problem for calculating the natural frequencies and the corresponding mode shapes...

...Gaute Storhaug; Erlend Moe; Gabriel Holtsmark Currently, the conventional wave loading is the only effect considered in fatigue assessment of ships. Det Norske Veritas (DNV) has recently confirmed that fatigue damage from wave induced vibrations may be of similar magnitude as from the conventional...