Download or read book System Identification of Offshore Marine Riser Due to Vortex Induced Vibration VIV written by Loganathan Radzakrishnan and published by . This book was released on 2014 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vortex Induced Vibration of a Marine Riser written by Xiangxi Han and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine riser is a key equipment connecting a floating platform and a seabed wellhead. Vortex-induced vibration (VIV) is the main cause of the fatigue damage of the riser. The prediction of marine riser VIV is very difficult because of its strong non-linearity, instability and uncertainty. In recent years, many numerical models of VIV of marine riser have been developed to explore the mechanism of marine riser VIV, providing scientific theoretical basis and practical engineering methods for vibration control and engineering design of marine riser. Combined with the authors,Äô own recent research, this chapter discusses the research progress on marine riser VIV in the ocean engineering, including phenomenon mechanism analysis and different numerical research methods.

Download or read book Time domain Simulation of Vortex induced Vibration for Deepwater Marine Risers written by Peter Ma and published by . This book was released on 2012 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Parametric Study of Vortex induced Vibration of a Long Flexible Marine Riser written by Anup Ghimire and published by . This book was released on 2008 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Simulation of Marine Risers with Vortex Induced Vibration written by Ryan Stuart Nicoll and published by . This book was released on 2006 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of the work described here is to analyse vortex induced vibration VIV) effects on marine risers and unorthodox forms of suppression of this phe?nomenon. which can cause structural failure through metal fatigue. Two suppression methods are explored: flex joints and buoyancy modules. Flex joints. which act like a hinge at a point on the riser due to the large reduction in bending stiffness. can suppress higher modes of vibration from propagating along or appearing in the riser. Buoyancy modules, with their local 100% increase in riser diameter. can decorrelate vortex shedding along the span of the riser and reduce the resonant effect of VIV. The numerical finite element cable model and rigid body model developed at the University of Victoria were modified and used as a foundation for the research. The modifications include an algorithm to estimate the forces clue to ocean surface interaction with rigid bodies and a model to produce the appropriate VIV response in the numerical cable model. The resulting VIV model was calibrated and validated with analytical. experimental, and numerical data available in the literature. In general. the model produces qualitative effects of VIV. including its self-starting and self-limiting nature, frequency lock-in. multi-mode response. and limited structural response on the order of one diameter. A simulation of a testbed riser in a variety of ocean currents was generated to observe the effects of installing flex joints and buoyancy modules at various locations along the riser span. The performance of the testbed riser was gauged by comparing the time series of von Mises stress and the associated safety factor, ns. from fatigue failure at many points along the span to an unmodified testbed riser. The stress fluctuation was drastically reduced within the flex joints for all water currents studied, which greatly increases fatigue performance. Flex joints placed at the top of the testbed riser had less impact. as the stresses are dominated by the large and unavoidable tensions found there. Flex joints placed in the bottom region of the riser did not affect the ns, . of the remaining riser span until very high modes of vibration were present. At these higher modes. some testbed riser configurations changed their vibration envelope and frequency. which indicates that a possible alternate and less damaging mode of vibration was induced. Flex joints therefore act effectively as a local patch against poor fatigue performance and placement of several flex joints does not negatively impact the behaviour of the rest of the riser in the cases examined. However. the explicit relationship between placement and spacing of flex joints with environment conditions remains unknown. Buoyancy modules introduced spatial fluctuations in the entire nu profile of the testbed riser, unlike flex joints. In addition. the buoyancy modules decreased n, performance due to the hydrodynamic load concentrations induced by their large diameters. However, the 16% coverage case increased n., . elsewhere along the riser, though the 10% covered riser did not match this performance. Since in both cases the modules were evenly spaced along the riser. performance benefits from increased coverage implies a minimum coverage of 16% needed for significant improvement in fatigue performance for devices of this type. This coverage requirement may apply to traditional VIV suppression devices such as helical strokes. since they decorrelate vortex shedding along the span of the riser albeit in a different manner than buoyancy modules. Finally. the buoyancy modules changed the stress oscillation frequency more than the flex joint cases from the unmodified riser. This is desirable since lowering the frequency of oscillation also increases the fatigue performance of the riser.

Download or read book Identification of Linear and Non linear Multi modal VIV Responses for Flexible Deepwater Risers written by Xiangqun Li and published by . This book was released on 2005 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Simulation of Marine Risers with Vortex Induced Vibration written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of the work described here is to analyse vortex induced vibration VIV) effects on marine risers and unorthodox forms of suppression of this phenomenon. which can cause structural failure through metal fatigue. Two suppression methods are explored: flex joints and buoyancy modules. Flex joints. which act like a hinge at a point on the riser due to the large reduction in bending stiffness. can suppress higher modes of vibration from propagating along or appearing in the riser. Buoyancy modules, with their local 100% increase in riser diameter. can decorrelate vortex shedding along the span of the riser and reduce the resonant effect of VIV. The numerical finite element cable model and rigid body model developed at the University of Victoria were modified and used as a foundation for the research. The modifications include an algorithm to estimate the forces clue to ocean surface interaction with rigid bodies and a model to produce the appropriate VIV response in the numerical cable model. The resulting VIV model was calibrated and validated with analytical. experimental, and numerical data available in the literature. In general. the model produces qualitative effects of VIV. including its self-starting and self-limiting nature, frequency lock-in. multi-mode response. and limited structural response on the order of one diameter. A simulation of a testbed riser in a variety of ocean currents was generated to observe the effects of installing flex joints and buoyancy modules at various locations along the riser span. The performance of the testbed riser was gauged by comparing the time series of von Mises stress and the associated safety factor, ns. from fatigue failure at many points along the span to an unmodified testbed riser. The stress fluctuation was drastically reduced within the flex joints for all water currents studied, which greatly increases fatigue performance. Flex joints placed at the top of the testbed riser had less impact. as the stresses.

Download or read book Dynamic Simulation of Marine Risers with Vortex Induced Vibration written by Ryan Stuart Nicoll and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of the work described here is to analyse vortex induced vibration VIV) effects on marine risers and unorthodox forms of suppression of this phe?nomenon. which can cause structural failure through metal fatigue. Two suppression methods are explored: flex joints and buoyancy modules. Flex joints. which act like a hinge at a point on the riser due to the large reduction in bending stiffness. can suppress higher modes of vibration from propagating along or appearing in the riser. Buoyancy modules, with their local 100% increase in riser diameter. can decorrelate vortex shedding along the span of the riser and reduce the resonant effect of VIV. The numerical finite element cable model and rigid body model developed at the University of Victoria were modified and used as a foundation for the research. The modifications include an algorithm to estimate the forces clue to ocean surface interaction with rigid bodies and a model to produce the appropriate VIV response in the numerical cable model. The resulting VIV model was calibrated and validated with analytical. experimental, and numerical data available in the literature. In general. the model produces qualitative effects of VIV. including its self-starting and self-limiting nature, frequency lock-in. multi-mode response. and limited structural response on the order of one diameter. A simulation of a testbed riser in a variety of ocean currents was generated to observe the effects of installing flex joints and buoyancy modules at various locations along the riser span. The performance of the testbed riser was gauged by comparing the time series of von Mises stress and the associated safety factor, ns. from fatigue failure at many points along the span to an unmodified testbed riser. The stress fluctuation was drastically reduced within the flex joints for all water currents studied, which greatly increases fatigue performance. Flex joints placed at the top of the testbed riser had less impact. as the stresses are dominated by the large and unavoidable tensions found there. Flex joints placed in the bottom region of the riser did not affect the ns, . of the remaining riser span until very high modes of vibration were present. At these higher modes. some testbed riser configurations changed their vibration envelope and frequency. which indicates that a possible alternate and less damaging mode of vibration was induced. Flex joints therefore act effectively as a local patch against poor fatigue performance and placement of several flex joints does not negatively impact the behaviour of the rest of the riser in the cases examined. However. the explicit relationship between placement and spacing of flex joints with environment conditions remains unknown. Buoyancy modules introduced spatial fluctuations in the entire nu profile of the testbed riser, unlike flex joints. In addition. the buoyancy modules decreased n, performance due to the hydrodynamic load concentrations induced by their large diameters. However, the 16% coverage case increased n., . elsewhere along the riser, though the 10% covered riser did not match this performance. Since in both cases the modules were evenly spaced along the riser. performance benefits from increased coverage implies a minimum coverage of 16% needed for significant improvement in fatigue performance for devices of this type. This coverage requirement may apply to traditional VIV suppression devices such as helical strokes. since they decorrelate vortex shedding along the span of the riser albeit in a different manner than buoyancy modules. Finally. the buoyancy modules changed the stress oscillation frequency more than the flex joint cases from the unmodified riser. This is desirable since lowering the frequency of oscillation also increases the fatigue performance of the riser.

Download or read book A Three dimensional Simulation of Vortex Induced Vibrations VIV on Marine Risers at High Reynolds Number Using Computational Fluid Dynamics written by Christopher Murrin and published by . This book was released on 2007 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Critical Review of the Intrinsic Nature of Vortex Induced Vibrations written by Turgut Sarpkaya and published by . This book was released on 2003 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a concise and comprehensive review of the progress made during the past two decades on vortex induced vibration (VIV) of mostly circular cylindrical structures subjected to steady uniform flow. The critical elements of the evolution of the ideas, theoretical insights, experimental methods, and numerical models are traced systematically; the strengths and weaknesses of the current state of the understanding of the complex fluid/structure interaction are discussed in some detail. Finally, some suggestions are made for further research on VIV. The organization of the paper is given at the end of the next section.

Download or read book A Three dimensional Simulation of Vortex Induced Vibrations VIV on Marine Risers at High Reynolds Number Using Computational Fluid Dynamics written by Christopher Murrin and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Subsea Pipelines and Risers written by Yong Bai and published by Elsevier. This book was released on 2005-12-05 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: • Updated edition of a best-selling title • Author brings 25 years experience to the work • Addresses the key issues of economy and environment Marine pipelines for the transportation of oil and gas have become a safe and reliable way to exploit the valuable resources below the world’s seas and oceans. The design of these pipelines is a relatively new technology and continues to evolve in its quest to reduce costs and minimise the effect on the environment. With over 25years experience, Professor Yong Bai has been able to assimilate the essence of the applied mechanics aspects of offshore pipeline system design in a form of value to students and designers alike. It represents an excellent source of up to date practices and knowledge to help equip those who wish to be part of the exciting future of this industry.

Download or read book Cont This Scatter Diagram Method Could Reduce the Cost of Risers by Reducing the Over Conservatism that is Introduced by the Common Practice of Using an Envelope Design Current Profile It Also Reduces the Analysis Time Required for the Brute Force Approach by Allowing the Designer to Focus on Only the Most Relevant Profiles written by Jessica Mary Donnelly and published by . This book was released on 2004 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes a scatter diagram approach for the classification of large numbers of current profiles for use 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 which current profiles have the combined property of long regions of relatively constant velocity and relatively high speed. A sorting algorithm is proposed which searches every current profile for long regions of relatively constant flow speed. The probability of each length and speed combination is assessed and the data is used to populate the bins of the scatter diagram. The designer need only select relatively few representative profiles for detailed VIV analysis from those bins that would account for the most damage. The method is tested by making comparison to a brute force approach in which each of many thousands of profiles is evaluated for fatigue damage by running it in the SHEAR7 VIV response prediction program.

Download or read book Wave Forces on Offshore Structures written by Turgut Sarpkaya and published by Cambridge University Press. This book was released on 2010-02-26 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a thorough understanding of the interaction of waves and currents with offshore structures.

Download or read book New Innovations in Engineering Education and Naval Engineering written by Nur M. S. Hassan and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Prediction of the Vortex induced Vibrations of Marine Riser written by and published by . This book was released on 2003 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book International Journal of Offshore and Polar Engineering written by and published by . This book was released on 2008 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: