  In this work, we study numerically the temporal evolution of an initially
random large-scale velocity field under governed by the hyperviscous
incompressible Navier-Stoke equations. Three stages are clearly observed during
the evolution. First, the initial condition development is characterized by a
spectrum evolving in a self-similar way with a wave number front $k_*(t)$
propagating toward high values exponentially in time. This evolution
corresponds to the formation and shrinking of think vortex pancakes
exponentially in time, as it has been previously reported in simulations of the
incompressible Euler equations. At the second stage, pancakes become unstable,
rolling up on the edges and breaking up in the middle, leading to the emergence
of vortex ribs -- quasi-periodic arrangements of vortex filaments. Those
filaments then twist creating structures akin to ropes. At the last stage, a
fully developed turbulent state is observed, characterized by a Kolmogorov
energy spectrum and exhibiting a decay law compatible with standard turbulent
predictions in the case of an integral scale saturated at the scale of the box.
