Design Optimization Of The Hull Forms Based On Completely Parametric Modeling And CFD

Ship hull forms design is a starting point of the design and construction process of the new shipbuilding and it is a critical step to overall design of ship.Ship hull forms not only influences ship performance,but also has dramatic effects on costs,the shipbuilding cycle,the energy consumption and safety considerations.Traditionally,ship hull forms design mainly uses parent ship to modify.Then the hull model is made according to modified hull forms and tested whether it meets the requirements by experiment.If the hull model satisfies requirements,the modified ship can be built,otherwise the modification of hull will be carried out again.This method causes the low quality and efficiency of ship design.Therefore,this not only extends the design cycle,but also adds to designers' burden.This paper confirms that the design optimization method of combination of CAD and CFD technology is applicable to ship hull forms design,which is based on completely parametric modeling.Research works in this dissertation are summarized as follows.(1)Hull geometry and characteristics of parametric modeling are analyzed so that the relationship between the relevant characteristics and performance of ship can be attained,and the characteristic parameters and characteristic curves of hull modeling can be determined.(2)The completely parametric modeling of the ro-ro ship is carried out.By using the parametric modeling method,the ship hull surface can be generated rapidly by using a few characteristic parameters.Meanwhile,through the modification of these parameters,the transformation of ship shape can be realized,so as to get a variety of hull.Therefore,the parameters of design optimization and ship hydrodynamic performance are related,so as to ensure the high quality and high efficiency of ship design optimization.(3)The wave-making resistance of ship is calculated with Rankine source method.The wave-making resistance performance of KCS and the ro-ro ship is calculated by numerical simulation method based on computational fluid dynamics(CFD).(4)The optimization of the ro-ro ship hull forms is accomplished,which is based on the CAD-CFD integration framework.According to the specific characteristics of ship,a reasonable optimization mathematical model is established.In order to ensure the global optimization and high efficiency of the search,a hybrid optimization strategy is proposed.By selecting design variables,constraint conditions and the hybrid optimization strategy proposed,the optimization of the ro-ro ship hull form is conducted,with the objective to minimize the wave-making resistance.Finally,the ship with more excellent performance of wave-making resistance is obtained.The proposed design optimization method of ship hull forms has important theoretical and practical significance to improve the quality of ship design,shorten the design time,and reduce the burden of design as well.