The first order wave forcing conditions applying in the domain can be specified on the Wave dialog.
In Final computation mode (see Section 1.3.2), the first order wave forcing will be taken fully into account in the wave pressure computation on the vessel hull. This should only be done when an initial vessel displacement has been achieved in advance, from running a previous simulation in convergence mode.
In Convergence mode (see Section 1.3.1), the first order wave forcing will be ignored in the wave pressure computation on the vessel hull. In Convergence mode the first order wave forcing can only be provided if including drift forces, and the first order wave forcing data will for this mode only be applied implicitly as part of the 2nd order drift forces computation.
By default the wave data is set to be included in the warm up and warm down durations as specified on the Time dialog.
Two formats for waves are supported:
· Varying in time, constant in domain
· Varying in time and domain
Regardless of which wave format is used, the wave forcing implementation relies on a user defined numbers of time steps involved in the Fast Fourier Transformation (FFT) size = 2^N, where the power N is the user defined part. This FFT size represents the minimum number of time steps from the wave file, which should be imported in order to properly dissolve the waves.
If 2nd order wave drift forces are available and included, it is required that wave data is provided in order to support the computation of drift forces.
If the wave file furthermore is specified as ‘Varying in time and domain’, you must also provide the Mean wave direction.
Wave file format
About FFT size