Hydrodynamic optimization of a triswach

A new methodology for hydrodynamic optimization of a Tri SWACH is developed, which considers not only the positions of the side hulls but also the shape of the side hulls. In order to account for the strong near-field interference effects between closely-spaced multihulls, an integrated hydrodynamic computational tool that consists of a potential-flow based simple CFD tool and an Euler/RANS/Navier-Stokes based advanced CFD tool has been further developed and integrated into a practical multiobjective hydrodynamic optimization tool. The other components of this hydrodynamic optimization tool consist of a hull shape representation and modification module and an optimization module. This enhanced multi-objective hydrodynamic optimization tool has been applied to the hydrodynamic design optimization of the Tri SWACH for reduced drag by optimizing the side hulls only. A new methodology is developed to optimize side hull forms so that the Tri SWACH has a minimal drag for a wide speed range and for various side hull positions. Two sets of the side hulls are developed and used for the design of two optimal Tri SWACH models. Model tests are carried out for two optimal Tri SWACH models at Webb Institute for validations. Substantial drag reductions have been obtained for a wide range of speed.