Efficient Full-Scale CFD for Ship Hydrodynamics

Doktorsavhandling, 2024

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.