COBEM99

S8 Engenharia Aeroespacial

Title:

A NUMERICAL-EXPERIMENTAL EVALUATION OF A FLEXIBLE RISER

Summary :

THE MAIN PURPOSE OF THIS WORK IS THE COMPARISON BETWEEN THE RESULTS FROM ANFLEX SIMULATIONS AND THE FULL SCALE DATA OBTAINED FROM A 8" FLEXIBLE RISER INSTALLED IN A SEMI-SUBMERSIBLE OIL PRODUCTION PLATFORM. THE DATA WERE ACQUIRED DURING SIX MONTHS, INCLUDING DISPLACEMENTS, ANGLES AND TENSION AT RISER TOP CONNECTION, MOORING LINE TENSIONS AND ENVIRONMENTAL DATA. FOR STATIC ANALYSIS, THE ANGLE AT TOP CONNECTION AND CURRENT ARE THE BASIC PARAMETERS. FOR DYNAMIC ANALYSIS, THE TENSION AT RISER TOP CONNECTION IS THE BASIC PARAMETER. FROM STATIC ANALYSIS, THE MAIN CONCLUSION IS THAT THE MATCH BETWEEN THE NUMERICAL AND EXPERIMENTAL RESULTS DEPENDS ON CURRENT VELOCITY: IT IS NECESSARY TO CONSIDER AN EFFECTIVE DRAG COEFFICIENT FOR THE FLEXIBLE RISER. FROM DYNAMIC ANALYSIS, THE EXPERIMENTAL RESULTS SHOWED THAT HIGH FREQUENCY (VIV) EFFECTS INCREASE THE DYNAMIC TENSION COMPONENT SIGNIFICANTLY, BUT THE SIMULATIONS FROM ANFLEX DO NOT CONSIDER THIS EFFECT. THE INFLUENCE OF STRUCTURAL AND FLUID DAMPING WERE ALSO INVESTIGATED.

Author :

Lopes, Tiago Piedras
Mourelle, Márcio Martins
Penny, Fábio Gomes

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