  In this paper we consider the properties of the internal partitions of the
nonlinear term, obtained when a filter with a sharp cutoff is introduced in
wavenumber space. We see what appears to be some degree of independence of the
choice of the position of the cutoff wavenumber for both instantaneous and
time-integrated partitioned nonlinearities. We also investigate the basic idea
of an eddy-viscosity model for subgrid terms and have found that while phase
modelling will be very poor, amplitude modelling can be far more successful.
