Statistical properties of the subgrid-scale stress tensor, the
local energy flux and
filtered velocity gradients are analysed in numerical simulations of forced
three-dimensional homogeneous turbulence. High Reynolds numbers are achieved
by using
hyperviscous dissipation. It is found that in the inertial range the subgrid-scale
stress
tensor and the local energy flux allow simple parametrization based on
a tensor
eddy viscosity. This parametrization underlines the role that negative
skewness of
filtered velocity gradients plays in the local energy transfer. It is found
that the local
energy flux only weakly correlates with the locally averaged energy dissipation
rate.
This fact reflects basic difficulties of large-eddy simulations of turbulence,
namely
the possibility of predicting the locally averaged energy dissipation rate
through
inertial-range quantities such as the local energy flux is limited. Statistical
properties
of subgrid-scale velocity gradients are systematically studied in an attempt
to reveal
the mechanism of local energy transfer.
Simultaneous observation of small- and large-energy-transfer electron-electron scattering in three-dimensional indium oxide thick films
