Optimization of Waterjet Propelled High Speed Ships - JHSS and Delft Catamatran

The present work focuses on the application of Simulation Based Design (SBD) for the resistance optimization of two waterjet propelled high-speed ships, namely, the Joint High Speed Sea-lift (JHSS) which is a monohull, and the Delft Catamaran (DC) at Fr=0.34 and 0.5, respectively. Design optimization has been performed for both the parent hull form and the waterjet inlets. The adopted SBD explores the concept of variable physics approach for the Delft catamaran which shows strong waterjet hull interaction effects. First a simplified CFD waterjet model is used to include the waterjet induced forces and moments during the bare hull Delft catamaran optimization. Next, the waterjet is appended to the optimized barehull and the inlet is optimized by detailed simulation of the duct flow. The bow shape optimization and waterjet inlet optimization of the JHSS were done independent of each other since waterjet hull interactions are weak, and the bow shape modification does not affect the local flow near the waterjet inlet. For JHSS, which has four side by side axial waterjets, the effect of combining the waterjet inlets on the powering performance was also explored. The design optimization yielded geometries with significant resistance reduction for both the JHSS and Delft catamaran. The final optimized Delft catamaran will be built and model tested to validate the SBD process.