Session: 16-10-01 Marine Hydrodynamics and Subsea Technology

Submission Number: 183621

Effects of Locked Double Splitter Plate Suppressors on Vortex-Induced Vibrations 

Vortex-induced vibrations (VIV) can impose large-amplitude oscillations on submerged structures exposed to flow, potentially leading to fatigue failure. One method of minimizing this problem in structures such as risers is the use of VIV suppressors that act to reduce these oscillations and the associated cyclic loading. Among the available solutions, double splitter plate (DSP) suppressors stand out, as they can simultaneously reduce oscillation amplitudes and drag when functioning properly, making them a widely used option in drilling risers. This geometry consists of a set of parallel plates that can rotate axially around the riser, allowing the angle to be aligned with the incident current and effective mitigation. However, a potential locking of the system can compromise its performance and intensify unwanted effects, which motivated experiments at a reduced scale to evaluate the influence of this condition. Initially, the model was kept fixed, varying the flow velocity and the incidence angle to determine the drag and lift coefficients. Subsequently, VIV tests were conducted to assess the effectiveness of the suppressor under different conditions and to identify its performance limit in adverse situations. The results show that the DSP maintains satisfactory performance up to approximately 20 degrees; as expected, increasing the incidence angle raises drag, and beyond this value, the oscillations associated with lift become significant, probably related to the galloping phenomenon. An original aspect of this study is the evaluation of the influence of the locked segments at the identified critical angle, where parts of the model were progressively positioned in this condition, allowing the determination of the suppressor’s efficacy threshold, considering combinations of modules in ideal and adverse conditions. The results highlight the impact of these adversities on the overall structural behavior, demonstrating that the DSP suppressor remains effective in mitigating VIV even with partially compromised segments, which provides a relevant indication for its application in real operations where partial failures may occur.

Presenting Author: André Fujarra Federal University of Santa Catarina

Presenting Author Biography: Professor Andre Fujarra has been an Assistant Professor at the Federal University of Santa Catarina (UFSC) since July 2015, having previously been an Associate Professor at the University of São Paulo (USP), 2003-2015. He earned his Naval and Ocean Engineering degree (1995), Master’s (1997), and Ph.D. (2002) from USP. He was also a Visiting Researcher at the University of Michigan (1999) and at MARIN in the Netherlands (2011-2012). His expertise is in Fluid-Structure Interactions, Hydrodynamics, and Dynamics of Offshore Systems, actively contributing to R&D projects on offshore structural dynamics and flow-induced vibrations.

Authors:

Gabriel de P. Dittrich Federal University of Santa Catarina
Elton A. E. da Maia Federal University of Santa Catarina
André Fujarra Federal University of Santa Catarina
Paulo V. R. Guilherme Petrobras
Stael F. Senra petrobras
Érico A. Santos Petrobras