1. Introduction
The use of numerical models for predicting the ship performance in preliminary design step is getting in common. The model experiments are still very valuable; hence, time and cost encourage the use of Computational Fluid Dynamics (CFD). In the past, CFD approaches were based on potential flow theory because the Navier–Stokes equation was difficult to solve. There are some approaches in solving Navier–Stokes equations, but recent developments in computing technology enable researchers to solve the problems in shipbuilding industry by means of Reynolds-Averaged Navier–Stokes (RANS) equations.