Numéro : 2710 - Year : 2017
Numerical optimization of hull forms and appendices
Sophie COACHE, David BELLEVRE, DGA – Techniques hydrodynamiques (Val de Reuil – France)
Pierre-Marie Guillouet, Naval Group (Lorient – France)
Propulsion performances are of the greatest importance to obtain an efficient ship. The hull form as well as the shape of its appendices determine the ship resistance and thus the required horse-power. This is why the optimization of the hull and its appendices shape is evaluated very early in the design of a ship. Historically, these optimizations were carried out via tests of various models in a towing tank. Nowadays, thanks to the step up of numerical capacities, these stages can be realized by using numerical simulation solvers (CFD). The first stage of this approach allows testing a higher number of shapes but also saving time for the choice of the optimized forms. The last stage of this optimization is the validation of a reduced number of hull forms in a towing tank. Within the framework of military ships, DGA-Th supports the designer Naval Group in order to optimize the hull form as early as the preliminary design phase. First of all, an optimization of the bare hull shape is carried out. The difficulty of this stage is to decrease the efforts applied to the hull while answering the functional constraints established by the designer. A new optimized form is then selected. Afterwards, the appendices are optimized according to the fluid streamlines on the hull and from its propellers. This article presents the method used for the optimization of the hull form and its appendices shape as well as its application on a frigate.