Virginia Tech Vortex-Induced Vibration Project |
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Home Prof. Ali H. Nayfeh of Virginia Polytechnic Institute and State University (VPI) and Dr. Robert M. Sexton of Starmark Offshore Inc. are working together on the development of a practical and reliable engineering method for the prediction of Vortex-Induced Vibration (VIV) on offshore slender structures. Project Proposal Interested organisations may participate in this project, as described in the project proposal. Please note the project objectives and project philosophy in the proposal. It is hoped that this project may focus energy and resources to the VIV area for offshore slender structures. The VPI VIV Project Participation Agreement is available here as a PDF file or as a .DOC file. The project seeks to develop a practical and reliable engineering method that captures the best of existing VIV technology for VIV analysis of offshore slender structures. To achieve this goal, a reduced-order VIV model will be developed that is similar in form to wake-oscillator VIV models but that is based on a rational theoretical foundation. The flexibility of the reduced-order VIV model permits the incorporation of future straightforward enhancements as additional data becomes available. Using techniques from nonlinear dynamics, nonlinear interactions, and nonlinear identification techniques, the form of the reduced-order model and the database of model coefficients will be developed based on data generated by Computational Fluid Dynamics (CFD) simulations and/or available measured data. The reduced-order model will be provided to project participants in the form of a software module that may be linked with existing riser dynamics analysis software (such as STARIS) and Finite-Element Analysis software. 2003 ASME Paper Initial results from the project are very promising and are described in the 2003 ASME paper. Note, initial project work has considered high Reynolds Numbers to 1,000,000. 2005 ASME Paper Results from the project continue to be very promising and are described in the 2005 ASME paper. The van der Pol model is shown to reproduce the transient lift and drag calculated with the CFD computer code. 2006 Journal of Vibration and Control Paper Results from the project continue to be very promising and are described in the 2006 Journal of Vibration and Control Paper. The refined reduced-order models for lift and drag offer considerable promise to discover more of the physics of Vortex-Induced Vibration. Presentation Slides Slides of the project presentation may be downloaded as a PDF file or as a Microsoft PowerPoint file. Note, the PowerPoint file works fine on Windows Microsoft PowerPoint but, unfortunately, not as well on the Apple Mac OSX Microsoft PowerPoint. ... So much for Microsoft compatibility... Virginia Tech Terascale Computer Cluster The Virginia Tech VIV project may use the Virginia Tech Terascale Computer Cluster to perform massive Computational Fluid Dynamics (CFD) calculations. The Terascale Cluster consists of 1100 nodes with each node composed of dual 2-GHz Apple PowerPC G5 CPUs. The Terascale Cluster runs the Apple OSX operating system and is presently considered one of the fastest and largest "homebuilt" supercomputers in the world. The Richmond Times Dispatch presents an article about Virginia Tech's "Big Mac" computer system which is the third fastest supercomputer. Click here for link to article. Spar Vortex-Induced Motion Workshop. Prof. Nayfeh discussed the VPI VIV project with potential project participants at the October 2003 Spar Vortex-Induced Motions Workship at Camp Allen, Texas. Photos show the interest in the project as well as Prof. Nayfeh's enthusiasm for the project. Click here for photos. Please contact Robert M. Sexton for more information about the Virginia Tech VIV Project. Contact Information. |
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