Development of Combatant Hull Form Generating Methods Using Logistic Function vs. Lamé Curve

This paper presents a ship hull form method based on analytic function. Without complex setting for design variables and errors caused by interpolation, continual functions are developed to define the frame of this ship and constraint boundary of section lines. Analytic functions for logistic curve and Lamé Curve are used as the basic form of section lines, respectively. The associated ship surface is modeled to check the effect of two forms of section lines. The continuity of functions for frames and section lines can guarantee the fairing of the ship surface. Extra hump (like bulbous or sonar dome) could also be modelled by the similar approach and appended to the bare hull using morphing technic. Fairing of the morphed surface can be controlled by varying the slope and location of the morphing edge. In the future, two function forms for section line can be combined together to improve flexibility of the surface modeling. This method also offers a direct access to generate the surface grid of the ship for CFD computation. Since the variables of the method are just the general parameters of the ship, that will be easy to be applied as the shape modification for optimization of ship with low dimension research space.