Numerical Exploration On The Effect Of The Hydrodynamic Drag Coefficient Upon Topside Loading In Steel Tube Umbilical Risers

In this work, the effect of the drag coefficient on the topside effective tension of an umbilical riser system is explored through batches of finite element analysis structural simulations of a typical riser system in Brazilian offshore ultra-deep waters. These simulations were performed in OrcaFlex, considering a steel tube umbilical riser cross-section. The drag coefficient is a determining factor of the system behavior and response to sea currents and it was found that its accuracy in global dynamic analyses of such systems could help streamline cross-section designs and correlate simulations to real-world applications. It was also found that a value of 1.2 for the drag coefficient could be interpreted as conservative for umbilical design and dynamic analysis.