  Observation of coronal EUV spectral lines sensitive to different temperatures
offers an opportunity to evaluate the thermal structure and flows in flaring
atmospheres. This can be used to estimate the partitioning between the thermal
and kinetic energies. Our aim is to model large-scale (50-10000km) velocity
distributions in order to interpret non-thermal broadening of different
spectral EUV lines. The developed models allow us to understand the origin of
the observed spectral line shifts and broadening, and link these features to
particular physical effects in flaring atmospheres. We use ideal MHD to derive
twisted magnetic fluxtube configurations in a stratified atmosphere. The
evolution of these fluxtubes is followed using resistive MHD, with anomalous
resistivity depending on the local density and temperature. The model also
takes into account the thermal conduction and radiative losses. The model
allows us to evaluate average velocities and velocity dispersions, which would
be interpreted as `non-thermal' velocities in observations, at different
temperatures for different parts of the models. Our models show qualitative and
quantitative agreement with observations. The line-of-sight (LOS) velocity
dispersions demonstrate substantial correlation with the temperature,
increasing from about 20-30 km/s around 1 MK to about 200-400 km/s near 10-20
MK. The average LOS velocities also correlate with velocity dispersions,
although they demonstrate a very strong scattering, compared to observations.
We also note that near foot-points the velocity dispersions across the magnetic
field are systematically lower than those along the field. We conclude, that
the correlation between the flow velocities, velocity dispersions and
temperatures are likely to indicate that the same heating mechanism is
responsible for heating the plasma, its turbulisation and
expansion/evaporation.
