PREDICTION OF HYDRODYNAMIC FORCES ON TLPS AT DIFFERENT ANGLES OF INCIDENCE

This paper reports on the prediction of the unsteady hydrodynamic forces that act on a floating Tension Leg Platform (TLP) due to the action of a steady current. The geometry of interest isshown schematically in Fig. 1. A Computational Fluid Dynamics (CFD) package is used to perform three-dimensional, time dependent simulations. The effects of turbulence on the flow field are accounted for using Large-Eddy Simulations (LES). Results are obtained for Reynoldsnumber (based on column diameter) of 7.5x106, which is a representative of those encountered in deep-sea operations [1, 2]. Experiments and field observations have indicated that the resulting flows exhibit a number of complicated features due to the existence of periodic vortex sheddingin the wake [3, 4, 5, 6, 7, 8, 9, 10, 11]. Many but not all of these features were captured by the present computations which utilized the Volume of Fluid (VOF) algorithm to track the evolution of the free surface [12]. An assessment of the importance of allowing for the movement of thefree surface rather than inhibiting it by the adoption of the more commonly used rigid-lid approximation is presented in this paper [2].

Keywords:

Computational Fluid Dynamics , Tension Leg Platform , Hydrodynamic Loads , Steady Current , Angle of Incidence