Experimental and Numerical Study of Wake Interference and Clashing Between Steel Catenary Risers

Abstract

The aim of this work is to estimate the risk of clashing between steel catenary risers (SCRs) due to wake interference. More generally, the validity of clearance analysis between risers as recommended by design codes is discussed. Considering the complexity of the problem, theoretical, numerical, and experimental approaches have been used jointly. Similitude rules have been investigated to reproduce wake induced oscillations (WIO) at model scale. Different regimes have been identified (stable, unstable, and critical) depending on the intensity and effects of WIO. The validity of steady wake models used in the industry is discussed in view of the experimental data. Finally, onset criteria for WIO and clashing are proposed based on comparison between experimental and numerical results.

Interference analysis and operability envelopes design for deepwater parallel strings

“…Even though the literature on the parallel strings collisions have little been reported for dual derrick operation, much research has been done on the riser interferences (DNV-RP-F203, 2009;Huse, 1993, 1996, Rustad et al, 2009. According to the previous experimental and numerical research, the Vortex-Induced Vibration (VIV), Wake-Induced Oscillation (WIO) and wake shielding effects are leading causes for riser interferences (DNV-RP-F203, 2009;Fontaine et al, 2013;Huang, 2010;Sumner, 2010;Wu et al, 2003). Sagatun et al (2002) presented a simulator to assess the collision probability for the adjacent risers closing to each other, considering the hydrodynamic interaction of WIO and VIV.…”