Hull Form Optimization for Reduced Drag and Improved Seakeeping Using a Surrogate-Based Method

In the present study, a CFD-based ship hydrodynamic optimization tool has been further developed by integrating a surrogate based method to the optimization module to optimize hull forms for reduced drag and improved seakeeping performance. Specifically, a radial basis function (RBF) based surrogate model is developed to approximate the objective functions (the drag and seakeeping performance) in the CFD-based hydrodynamic optimization of ship hull forms. In order to construct the RBF-based surrogate model, a practical steady ship flow solver (SSF) based on the Neumann-Michell theory and a ship motion program (SMP) based on the strip theory are employed to evaluate the drag and the seakeeping performance of the sampling hull forms, respectively. For the purpose of illustration, the developed tool is applied to the optimization of the Series 60 hull, where the original Series 60 hull with an added bulbous bow is taken as an initial hull to be optimized by minimizing the drag, the heave motion and the pitch motion when the ship advances at a constant forward speed in head seas. Numerical results show that the present computational tool can be used to optimize ship hull forms for reduced drag and improved seakeeping performance, and the developed RBF-based surrogate model can reduce computational costs associated with the CFD runs.