  Direct and large eddy simulations of hydrodynamic and hydromagnetic
turbulence have been performed in an attempt to isolate artifacts from real and
possibly asymptotic features in the energy spectra. It is shown that in a
hydrodynamic turbulence simulation with a Smagorinsky subgrid scale model using
512^3 meshpoints two important features of the 4096^3 simulation on the Earth
simulator (Kaneda et al. 2003, Phys. Fluids 15, L21) are reproduced: a k^{-0.1}
correction to the inertial range with a k^{-5/3} Kolmogorov slope and the form
of the bottleneck just before the dissipative subrange. Furthermore, it is
shown that, while a Smagorinsky-type model for the induction equation causes an
artificial and unacceptable reduction in the dynamo efficiency,
hyper-resistivity yields good agreement with direct simulations. In the
large-scale part of the inertial range, an excess of the spectral magnetic
energy over the spectral kinetic energy is confirmed. However, a trend towards
spectral equipartition at smaller scales in the inertial range can be
identified. With magnetic fields, no explicit bottleneck effect is seen.
