Optimization of ship hull based on wave making resistance

Abstract

A numerical program is developed to optimize the ship hull based on wave making resistance. Ship hull geometries are modified to optimize the hulls within a limit to maintain the design criteria. In this work, a non-uniform rational b-spline (NURBS) based hull surface is taken as the input for optimization. MAPS resistance is a potential theory based program that uses a modified Dawson method to calculate wave making resistance. An automatic hull discretization system is developed for calculating wave making resistance by MAPS resistance. Two different algorithms, Path of steepest descent (PSD) and Broyden–Fletcher–Goldfarb–Shanno (BFGS) are employed for optimization. At first the PSD is used for optimization. Later on a BFGS algorithm is applied with the help of a Kriging technique to reduce the computational time and expense. Three different kinds of hull modification methods are introduced to optimize the ship hull. Multiple ship hulls are used for validating the optimization technique. All the ship hulls produced satisfactory results by decreasing the wave making resistance. The optimal hulls are further investigated for a series of Froude numbers to compare their wave making resistance with published experimental data.