This paper is a continuation of our previous paper [1] (OMAE2013-11569) where we demonstrated a state-of-the-art methodology for predicting the motions and loads of subsea equipment and structures during offshore operations basing on time domain simulations of subsea equipment and structures. Instead of relying on simplified equations or empirical formulations to calculate and estimate the hydrodynamics coefficients, or using steady-state CFD simulation on a stationary equipment and structure to predict drag and added masses on submerged structures in traditional approaches, this methodology couples the transient CFD with diffraction analysis. The time domain diffraction simulation is coupled with multiphase CFD simulation of subsea equipment and structures in waves. Transient CFD model with rigid body motion for the equipment and structure calculates added masses, forces and moments on the equipment and structure for diffraction analysis, while diffraction analysis calculates linear and angular velocities for CFD simulation. In this paper, parametric studies are performed to investigate effect of wavelength, wave amplitude and wave current on the motion of a hollow cylinder in waves. The results of the parametric studies in this paper show wave-structure interaction of a hollow cylinder in waves, and the effect of waves and current on the motion of the cylinder and the associated forces. The results provide better understanding of structure motion and associated forces in waves using this coupled methodology. The coupled methodology eliminates the inaccuracy inherited from assumed or calculated hydrodynamic properties that are obtained by using simplified equations or empirical formulations [2], or by using steady-state CFD analyses in traditional decoupled approaches. The results show that the coupled physics of wave and cylinder motion is captured by using this methodology, otherwise is not captured by traditional approaches. This coupled methodology has potential applications in analyses of the motions of subsea equipment and structures in wave during offshore operations.
Nonlinear time‐domain wave‐structure interaction: a parallel fast integral equation approach
