CFD-Based Optimization for Minimal Power and Wake Field Quality

This paper discusses a procedure to optimize ship hull forms for minimum required power and best wake field quality, based on CFD computations of the viscous flow and resistance. A flexible and effective definition of parametric hull form variations is used, based on interpolation between basis hull forms. The RANS solver parnassos is used, and the computations are done in parallel on hundreds of processors, permitting short turnaround times. Care is taken that the computed trends are not influenced by numerical disturbances coming from grid dependence, insufficient convergence or automatic grid generating procedures. Clear Pareto fronts, trends in the solutions and scale effects on those trends are obtained in a systematic variation study for a tanker afterbody. It appears that a significant reduction of both the resistance and the estimated required power can be obtained. The computed improvements in the resistance and in the nominal wake field show excellent agreement with measurements.