Development Of Hull Form Deformation Module In Numerical Optimization Software OPTShip-SJTU

In recent years,a lot of energy-saving measures have been proposed and applied for the tight supply of energy and the awakening of environmental consciousness.The optimization of hull form is one of the methods and it is also the focus in present research.The biggest goal is to improve the hydrodynamic performances of ship by modifying the hull form globally or locally while the main geometric features,such as main dimensions,displacements and wetted areas,are set as fixed.Previously,in order to obtain a good hull form,ship designers had to try a large of combinations of design variables to search for the optimal solution through experimental tests,however,this method is considered to be too inefficient and less accurate.With the development of numberical methods and computer techniques,engineers have developed various hull form optimization tools with different hydrodynamic analysis methods,geometrical deformation techniques and optimization algorithms,and these tools have been presented and applied in a huge body of literature.It is important to use several appropriate and effective surface modification methods during the optimization processing.The deformation of ship surface is the beginning of optimization and the link between hydrodynamic performance evaluation module and optimization algorithm.Accordingly,the design and development of surface modification module are of crucial importance.In present study,several modification methods including shifting method,Lackenby method,weight blending method,free form deformation method,radial based function method have been developed with C++ programming language based on sufficient research study.The users can use any method or combination of methods to deform the hull surface.Then,the surface modification module has been integrated into an optimization tool named OPTShip-SJTU with other function modules including hydrodynamic performance evaluation module,approximation module and optimization algorithm module.Several benchmark cases have been carried out to validate the reliability of surface modification module and OPTShip-SJTU,and a RANS-based CFD solver naoe-FOAM-SJTU are utilized here to examine the optimization results.