Efficient Full-Scale CFD for Ship Hydrodynamics

Abstract: An efficient numerical approach for ship hydrodynamics, involving a hybrid free-surface potential flow/RANS method, is explored. The work focuses on estimating the delivered power of ships in calm water and in waves, highlighting the benefits of full-scale simulations, particularly for ships with Energy Saving Devices. The robustness and accuracy of the approach are confirmed by verifications and validations at both model and full-scale, showing uncertainties significantly lower than in typical sea trial data, with comparison errors within a few percent. This is attributed to the discretization, structured grids and solving the steady RANS equations in a coupled manner. Special attention is paid to hull roughness effects in the simulations, a critical factor in ship resistance. Efficiency variations of different Energy Saving Devices between model and full scale, notably influenced by Reynolds number dependency, are also highlighted. The method demonstrates effectiveness across various cargo ship types and conditions, suggesting its suitability as a reliable and practical tool for ship designers for full-scale hydrodynamic performance evaluation and optimization. It complements physical testing and more expensive, unsteady RANS methods.