Predicting Loads on a LNG Carrier With CFD

Abstract

The Current Affairs Joint Industry Project was initiated to develop the understanding and tools for the assessment of current loads on offshore structures. CFD is one of these tools requiring a good understanding of the underlying physical and mathematical models. In order to assess its suitability for the prediction of current loads on monohulls, the flow around a LNG carrier for which model scale data is available was considered. The LNG carrier, including bilge–keels and rudder, was towed at scale 1/50 in Marin’s shallow water basin during the HAWAI JIP, for flow angles between 0 and 180 degrees. The measurements were shared with the Current Affairs JIP, for which the participants were invited to perform CFD computations reproducing the model test results. A number of these simulations are presented in this paper. The analysis of the results includes discussion on the grid generation as well as the numerical and physical parameters of the simulation. The comparison between experiments and computations shows that CFD can provide good qualitative predictions for the variation of force coefficients with inflow angle. The origin of the result variability between the participants is discussed and attention is drawn to the different factors influencing the quality of the simulation.