When selecting sinusoidal waves, the periods obtained do not match those requested

Wind & Water Computer-Aided Engineering Software Tools
1

Dear all.

I’m sure it’s a very simple issue in some parameter, but it has slipped my mind. When selecting regular waves to get the RAOs, the periods obtained in wave1elev do not match those requested. The higher the period of the wave, the lower the agreement.

Here are some examples of the periods obtained, when in fact the periods requested were round figures:
33.37
35.329412
37.53750026
40.04
42.9
46.2
50.05
54.6
60.06
66.73333225
75.075
85.8

Thank you very much for your help.

Best regards
Iñaki

2

Dear @Inaki.Zabala,

When WaveMod = 1 for regular waves, HydroDyn will round WaveTp to the nearest frequency used by the internal FFT, with the frequency step determined by df = 1/WaveTMax (in Hz). So if you want the exact period you specify to be used, ensure WaveTMax is an integer multiple of WaveTp when using WaveMod = 1 for regular waves.

Best regards,

3

Thank you Jason!

I smelled something like that, but you hit the nail on the head.

Best regards
Iñaki