CFD High L/D Riser Modeling Study

Abstract

Fully three dimensional fluid flow simulations are used with a simple structural model to simulate very long risers. This method overcomes many shortcomings of methodologies based on two dimensional flow simulations and can correctly include the effects of three dimensional structures such as strakes, buoyancy modules and catenary riser shapes. The method is benchmarked against laboratory and offshore experiments with model risers of length to diameter ratios up to 4,000. RMS values of vortex induced vibration motions are shown to be in good agreement with measurements. The resources needed to model ultra deep water drilling and production risers are estimated based on current computer technology.

High aspect ratio (L/D) riser VIV prediction using wake oscillator model

“…Comparisons of the calculations employing wake oscillator model with experiments (Trim et al, 2005;Lie and Kaasen, 2006) and CFD method (Holmes et al, 2006;Constantinides et al, 2007) are carried out. The focus is on evaluating the capability of the wake oscillator to reproduce some predictions from CFD models.…”

“…Furthermore, the method has had some success in comparison with experiments such as that reported by Yamamoto et al (2004), Meling (2004, 2005), Willden and Graham (2005). Holmes et al (2006) and Constantinides et al (2007) used fully 3-D CFD simulations coupled with relatively simple structural models to predict high aspect ratio riser VIV, achieved reasonably well results, and demonstrated the possibility of calculating riser VIV using full 3-D CFD approach.…”

“…Holmes et al (2006) and Constantinides et al (2007) attempted to use fully 3-D CFD simulations coupled with relatively simple structural models to predict riser VIV. This approach bypasses the main objections to the strip method but introduces new difficulties associated with the size of the numerical solution.…”

Challenges for a Total System Analysis on Deepwater Floating Systems

“…In order to implement more advanced design of risers [61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77] in practice, the current development of riser technology is advancing the coupled riser FE/CFD numerical analysis, in parallel with small-scale laboratory, and larger scale or full-scale in-situ testing. In addition, several commercially available large CFD programs are updated to make them more suitable for offshore applications.…”

Wind-structure interaction simulations of ovalling vibrations in silo groups

“…for the optimization of artificial respirators [112,269]. In civil engineering, offshore applications such as flow-induced vibrations of offshore risers [49,75,108,289] and ocean current-driven or wave energy converters [52,181,190] have been considered. The study of wind-induced vibrations finally was for a long time focussed on flutter of long suspension bridges [155,190,267] but is also used to investigate flexible membrane structures in wind flows [27,103,167,284,286] and for aeroelastic studies of wind turbine rotors [37,98].…”