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Technology
Assessment & Research (TA&R) Program
| Project Number |
481 |
| Date of Summary |
February 5, 2008 |
| Subject |
CFD Simulation of Riser VIV |
| Performing Activity |
Texas A&M University and OTRC |
| Principal Investigator |
Hamn-Ching Chen, Chia-Rong
Chen, Kevin Huang, and R.Mercier |
| Contracting Agency |
Minerals Management Service |
| Estimated Completion |
Complete |
| Description |
Vortex-induced vibration (VIV) is an important issue in the design of
deepwater riser systems, including drilling, production and export risers.
The VIV can produce a high level of fatigue damage in a relatively short
period of time for risers exposed to severe current environments. The wake
interference between various risers in the same riser array may also lead to
collisions between adjacent risers. Suppression devices, such as helical
strakes or fairings may be needed to prevent unacceptable levels of fatigue
damage. The purpose of this four phase
research effort was to research and to
develop advanced computational fluid dynamics (CFD) tools and
modeling that provide reliable prediction of riser VIV in ultra deep
water environments. |
| Progress |
Phases I & II
performed three-dimensional VIV
simulations using Large Eddy Simulation. The simulations were
performed for low aspect ratio cylinders with periodic boundary conditions
using up to 2 million grid points. The focus was
to develop a
quasi-three-dimensional VIV simulation program, where the riser was
modeled as an elastic structure which can deform axially and
transversely. During
Phases
III and IV, the riser structural
deformation was calculated using (a) modal decomposition with pre-defined
mode shapes, and (b) direct
integration of the tensioned beam motion equation. CFD simulations were
performed and compared with
available experimental data to illustrate the capability of the present
CFD approach for accurate prediction of the motion responses of flexible
long risers. It was found that the riser could experience multi-mode VIV
under uniform current condition. The simulation results demonstrated that
the present CFD approach is suitable for VIV analysis of deepwater risers
with large L/D and complex current conditions.
Project completed in December 2007. |
| Reports |
|
AA (66 pages) |
CFD Simulation of Riser VIV, OTRC
Library No. 10/2006A176,
submitted by Hamn-Ching Chen, Chia-Rong
Chen, and Richard S. Mercier of the
Texas A&M University, Offshore Technology Research Center (OTRC), College
Station, TX, December 2006. |
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AB
(86 pages) |
CFD
Simulation of Riser VIV, OTRC
Library No. 12/2007A186,
submitted by Hamn-Ching Chen, Chia-Rong
Chen, Kevin Huang, and Richard S.
Mercier of the Texas A&M
University, Offshore Technology Research Center (OTRC), College
Station, TX, December 2007. |
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