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Sensitivity of marine riser response to the choice of hydrodynamic coefficients

Conference · · Offshore Technol. Conf.; (United States)
OSTI ID:5482382

The sensitivity of the response of typical marine risers to choices of hydrodynamic coefficients is assessed. A time and frequency domain study of typical drilling and production risers for water depths from 500 to 3000 feet investigates the influence of the technique used to include the hydrodynamic coefficients in the riser program as well as the value of the coefficients for a range of environmental conditions. Data are presented to guide the designer and analyst in determining how to model the riser hydrodynamic coefficient and how accurately the coefficients must be known. The results of the study show that for most cases, constant coefficients based on the maximum values of Reynolds and Keulegan-Carpenter numbers occurring anywhere along the riser are sufficient for determining operating parameters such as top tension and base angle. For those designs where fatigue life or clearance with adjacent structures is critical, more sophisticated techniques using coefficients based on local Reynolds and Keulegan-Carpenter numbers may be necessary. Overall, the study shows that riser responses are generally insensitive to the values of the hydrodynamic coefficients used to predict the motions. Fatigue life and clearance with adjacent structures can be affected if the uncertainty in the coefficients is sufficiently large.

Research Organization:
Standard Oil Co. of California
OSTI ID:
5482382
Report Number(s):
CONF-830514-
Journal Information:
Offshore Technol. Conf.; (United States), Journal Name: Offshore Technol. Conf.; (United States) Vol. 3; ISSN OSTCB
Country of Publication:
United States
Language:
English