Hollm, MartenMartenHollmSeifried, RobertRobertSeifried2023-09-122023-09-122023-10Proceedings in Applied Mathematics & Mechanics 23 (2): e202300141 (2023)https://hdl.handle.net/11420/43253The hydrodynamic forces acting on prescribed free‐floating mechanical systems are studied. Regular and irregular sea states are considered using Stokes wave theory of first and second order. It is analyzed how much the magnitude and temporal behavior of the forces can differ using nonlinear theories of different orders instead of the linear wave theory. The corresponding effects on the mechanical dynamics of the system are investigated. Therefore, the fluid–structure interaction and hydrodynamic forces are computed, solving the corresponding partial differential equations of the linear and nonlinear wave theory. In this way, the nonlinear interactions of the different wave components in irregular seas and the disturbances of the sea due to the presence of the mechanical system are captured.en1617-70612023219Wileyhttps://creativecommons.org/licenses/by/4.0/EngineeringJournal Article10.15480/882.856010.1002/pamm.20230014110.15480/882.8560Journal Article