Doubt regarding the dealiasing technique about hos-nwt HOT 1 CLOSED

@rickyspaceguy
This is a relevant question. The choice is somewhat arbitrary since the additional potential at the free surface is actually evolving as cosh(k(Lx-x)) which is neither a sin nor a cosine function of x.
It is consequently expected that the decomposition of this additional potential on such basis is converging with respect to the number of points and that the dealiasing technique adopted is correct in the removal of aliasing errors in the products appearing in the free surface boundary conditions. Then, you for sure have to use the same eigenfunctions for both Fourier and inverse fourier to get correct results.

With respect to the use of reduce, it is actually not transforming back to physical space the quantity of interest, it only works in the modal space.

Best regards,

Guillaume

from hos-nwt.