Group velocity for regular waves generated in deep water

[Cluain]

Does group velocity effect long linear waves generated by a paddle generating waves in deep water?
I have developed a numerical wave tank in CFD at full scale, using a bottom hinged flap paddle that oscillates to produce regular waves, the domain is roughly three wavelengths long, and a beach is provided at the end to dissipate the energy by wave breaking and prevent reflection.
The paddle oscillates with a constant period and amplitude, to create water waves of a corresponding period and amplitude. The generated waves do not appear to be quite constant and I was wondering if group velocity was affecting them or if group velocity is not relevant in this case.

 

[olivermsun]

If they are true deep water waves, then yes there is dispersion and hence there is a distinct group velocity. But what do you mean the generated waves are not quite constant? Do you have a plot?