Improving the hydrodynamic performance of stepped hulls through enhanced analysis techniques

The inclusion of steps presents an attractive solution to improving the efficiency of high-speed planing vessels, yet analysis tools and the available knowledge for improving stepped hulls are considerably under-developed. The research presented in this thesis addresses these issues, seeking answers to the question: “How can we enhance and accelerate analysis techniques for stepped hulls through knowledge developed from numerical simulations and can hydrodynamic performance be improved through the application of these tools.” The studies in this thesis apply state-of-the-art Fluid Dynamics (CFD) to examine the impact that the addition of steps has to a planning hull, investigating the mechanisms through which efficiency is improved. The fluid flow is analysed as it separates at each step and interacts with the remainder of the hull, with existing methods of modelling this behaviour being evaluated and novel modelling strategies being proposed. The knowledge established through these investigations is applied to develop mathematical models for the performance prediction of single and double-stepped planing hulls, aiming to address the limitations and enhance the accuracy of those currently available. The proposed models displayed high degrees of accuracy, calculated the resistance with an average error of 2.50% and 1.29% respectively for single and double stepped hulls. The enhanced analysis techniques are applied to investigate how the hydrodynamic performance of single and double stepped hulls may be improved. This was successfully achieved, identifying design trends and establishing relationships between design parameters that may be universally applied by designers to lower the resistance of stepped hulls.The inclusion of steps presents an attractive solution to improving the efficiency of high-speed planing vessels, yet analysis tools and the available knowledge for improving stepped hulls are considerably under-developed. The research presented in this thesis addresses these issues, seeking answers to the question: “How can we enhance and accelerate analysis techniques for stepped hulls through knowledge developed from numerical simulations and can hydrodynamic performance be improved through the application of these tools.” The studies in this thesis apply state-of-the-art Fluid Dynamics (CFD) to examine the impact that the addition of steps has to a planning hull, investigating the mechanisms through which efficiency is improved. The fluid flow is analysed as it separates at each step and interacts with the remainder of the hull, with existing methods of modelling this behaviour being evaluated and novel modelling strategies being proposed. The knowledge established through these investigations is applied to develop mathematical models for the performance prediction of single and double-stepped planing hulls, aiming to address the limitations and enhance the accuracy of those currently available. The proposed models displayed high degrees of accuracy, calculated the resistance with an average error of 2.50% and 1.29% respectively for single and double stepped hulls. The enhanced analysis techniques are applied to investigate how the hydrodynamic performance of single and double stepped hulls may be improved. This was successfully achieved, identifying design trends and establishing relationships between design parameters that may be universally applied by designers to lower the resistance of stepped hulls