Speed and delivered power in waves — Predictions with CFD simulations at full scale
Journal article, 2023

An efficient numerical method is proposed to estimate delivered power and speed loss for a ship in wind and waves. The added resistance in waves, obtained with an unsteady potential flow panel method, is added to the calm water resistance from a steady-state potential flow/RANS method coupled with a body force propeller model for self-propulsion. A comparison of numerical and experimental results is made for added resistance, calm water resistance and delivered power. A good agreement is obtained. As a practical application, the approach is used to calculate the weather factor, fw, of the Energy Efficiency Design Index (EEDI). The calculated weather factor is consistent with the values derived from full-scale measurements included in a database of similar ships.





Weather factor


Speed loss

Delivered power



Michal Orych

Flowtech International AB

Chalmers, Mechanics and Maritime Sciences (M2), Marine Technology

Magnus Östberg

Flowtech International AB

Martin Kjellberg

RISE Research Institutes of Sweden

Sofia Werner

RISE Research Institutes of Sweden

Lars Larsson

Chalmers, Mechanics and Maritime Sciences (M2), Marine Technology

International School of Yacht Design – ISYD AB

Ocean Engineering

0029-8018 (ISSN)

Vol. 285 115289

Improved digital tools for the hydrodynamic design of energy efficient ships – validation, demonstration and introduction to the maritime industry

Swedish Energy Agency (49300-1), 2020-01-01 -- 2021-12-31.

Areas of Advance


Subject Categories

Vehicle Engineering

Marine Engineering



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