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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 32 for “"vortex-induced vibration"”.
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Airfoil Vortex Induced Vibration suppression devices
Vortex Induced Vibrations (VIV) is a major concern of the offshore oil industry. This problem leads to fatigue failure in the marine risers and causes costly replacement of the risers. Appendages such as helical strakes have proven that VIV can be eliminated but at the cost of increased drag. …
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Modeling Vortex -Induced Vibration of Long -Span Bridges
… current techniques for the prediction of vortex-induced vibration of non-circular sections representative of bridge decks. Wind tunnel experiments of six spring-mounted rigid section models were performed in order to further advance the understanding of the mechanism of vortex-induced …
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Vortex-induced vibration of slender structures in unsteady flow
Vortex-induced vibration (VIV) results in fatigue damage of offshore oil exploration and production structures. In recent years, the offshore industry has begun to employ curved slender structures such as steel catenary risers in deep-water offshore oil systems. The top-end vessel motion causes the …
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Vortex-induced vibration of flexible cylinders in sheared flows
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1988.
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Simulation of vortex induced vibration of a bluff body structure
Understanding Vortex induced vibration (VIV) phenomenon is essential as it plays important role in designing marine risers which used in oil extraction from the seabed to the offshore platforms were exposed to external flows that may trigger dangerous VIV oscillations. The present two-dimensional …
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Vortex-induced vibration of flexible cylinders in time-varying flows
This thesis investigates two aspects of Vortex-Induced Vibrations (VIV) on long flexible cylinders. The work is split into a minor and major part. The minor part addresses the effect of Reynolds number on flexible cylinder VIV. The major contribution addresses the prediction of VIV under unsteady …
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Characterization, modeling and mitigation of vortex-induced vibration of slender cylinders
… at large amplitudes under wind excitation. Vortex-shedding was found to be one of the primary excitation mechanisms which manifests itself as distinct characteristics of the resultant problematic vibrations. The objectives of the proposed research are to formulate a methodology for …
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Vortex-induced vibration of a linearly-sprung cylinder with nonlinear energy sinks
… circular cylinder undergoing rectilinear vortex-induced vibration (VIV) normal to the mean flow. The attachment is a nonlinear energy sink (NES). The essentially nonlinear coupling between the rectilinear motion of the cylinder and the motion of the NES allows for efficient, one-way …
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The flow of power in the vortex-induced vibration of flexible cylinders
… regions of long cylinders exposed to flow-induced vibration. The data used to illustrate the techniques come from a set of vortex-induced vibration model tests conducted by Shell Oil Co in 2011 at the Marintek facility in Trondheim, Norway. The identification of power-in regions allows one …
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Effect of traveling waves on Vortex-Induced Vibration of long flexible cylinders
… exposed to ocean currents, are susceptible to Vortex-Induced Vibration (VIV). Accurate prediction of VIV is necessary for estimating the fatigue life as well as for taking corrective measures to prevent the vibrations. State of the art response prediction methods work reasonably well for short …
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Study of reduced order models for vortex-induced vibration and comparison with CFD results
Vortex-induced vibration (VIV) is a dynamic phenomenon that can occur when there is fluid flow past a bluff body with flexibility. Over time, VIV can cause fatigue damage, so it may be desirable to suppress these vibrations. It is important to understand how the system behaves when trying to …
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Vortex-induced vibration of a circular cylinder with combined in-line and cross-flow motion
… subject to strong ocean currents, suffer from vortex-induced vibrations (VIV), where vortex shedding interacts with the structural properties of the riser, resulting in large amplitude vibrations in both in-line and cross-flow directions. This thesis presents an experimental approach to model …
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Vortex-induced vibration of marine risers : motion and force reconstruction from field and experimental data
Vortex-induced vibration (VIV) of long flexible cylindrical structures enduring ocean currents is ubiquitous in the offshore industry. Though significant effort has gone into understanding this complicated fluid-structure interaction problem, major challenges remain in modeling and predicting the …
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Learning hydrodynamic coefficient databases for vortex induced vibration prediction of marine risers using sparse sensor measurements
… technology for flexible cylinder vortex induced vibrations (VIV) predictive modelling. Accurate prediction of the structural response relies heavily on the accuracy of the acquired hydrodynamic coefficient database. Due to the large number of inputs required, the construction of …
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Modeling the effects of Reynolds number and added mass on the vortex-induced vibration of drilling risers
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000.
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Investigations on Vortex-induced Vibration (VIV) Phenomena of Single-and-double-cylinder Flexible Beam Arrangements of Energy Harvesters
… energy-harvesting, which converts mechanical (vibration) into electric energy, is the fastest development one in recent years.</p> <p>In our current work, a piezoelectric harvester with a finite length cylinder fixed to one end of a flexible thin beam, is the research object in an incoming flow …
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A scatter diagram approach to the selection of design currents for prediction of marine riser vortex-induced vibration
… in the prediction of riser fatigue damage due to vortex-induced vibration. Scatter diagrams have long been used to characterize the probability of various combinations of wave height and period, which are then used to assess wave forces. To predict VIV fatigue damage the designer needs to know …
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Multi-frequency cable vibration experiments
A series of Multi-Frequency cable vibration experiments at Reynolds number 7600 were carried out at the MIT Tow Tank using the Virtual Cable Towing Apparatus (VCTA). Motions observed in a Direct Numerical Simulation of a flexible cylinder in a shear current were imposed on the VCTA and force …
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Passive wake detection using seal whisker-inspired sensing
… to accomplish this detection. Key are the unique vortex-induced vibration (VIV) properties resulting from the geometry of the harbor seal whisker. First, force measurements and flow visualizations on a rigid whisker model undergoing 1-D imposed oscillations show that the geometry passively reduces …
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Visualization of vibration experienced in offshore platforms
… methods to optimize the visualization of vortex-induced vibration (VIV) in marine risers. VIV is vibration experienced by marine risers in offshore drilling platforms due to ocean current flows, and appears to be perpendicular to the direction of such flows. VIV causes oil companies large …
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