rippled water level

Question

I am getting rippled sea level at the surface, I would like to know if the cd-drag coefficient of the wind could  disappear it

I am also not getting a good resolution for tide currents which BC will work better?

Answer 1

I'm not 100% sure what causes the surface rippling sometimes but I think its a numerical artefact of the implicit free surface solution when thin surface cells are involved.  

you can sometimes mitigate it if you can centre the surface level within a layer if your tidal changes is not too large.