Calculation of ship motions in steep waves with restoring and Froude-Krylov forces on an adaptive panel mesh with Gauss and analytic integration methods

Journal
Journal of hydrodynamics  
Volume
36
Issue
2
Start Page
275
End Page
289
Citation
Journal of Hydrodynamics 36 (2): 275-289 (2024)
Publisher DOI
10.1007/s42241-024-0026-6
Scopus ID
2-s2.0-85194954444
Publisher
Springer
The impulse response method is a frequently used method to calculate ship seakeeping behavior. In this paper, the restoring and Froude-Krylov calculation is conducted with constant evaluation of panel pressures as well as Gauss quadrature and an analytical integration. The applied panel grid is coarsened by an adaptive algorithm which is based on a normal vector condition. The comparison of methods is based on grid convergence studies which are followed by a verification of forces with computational fluid dynamics (CFD) results on the fixed duisburg test case in waves. Validations with experimental results in head, oblique and following waves show that all integration methods are accurate. The exact integration is numerically sensitive in some cases. Gauss quadrature is highly accurate; however, the additional effort is not beneficial since the geometrical accuracy has-stronger influence on the force amplitudes than the integration method. Adaptive grid coarsening reduces the simulation time and is accurate up to a level, where the panel length comes close the wavelength. The added resistance at the investigated Froude number of 0.05 shows higher uncertainty levels, this applies to the results of both the numerical methods and model tests.
Subjects
added resistance
impulse response method
seakeeping
Ship hydrodynamics
wave loads
DDC Class
600: Technology