: drag coefficient
: inertia coefficient
: lift coefficient
: frequency of incident wave
Morison's equation:
Linear forces on vertical pile:
with:
where:
Stokes forces (non-linear) on vertical pile:
and 
are given from figures 7-71 and 7-72 of SPM
where 
is given from Figures 7-76 to 7-79 of SPM
for different 