  We have performed Coherent-vorticity Preserving Large-Eddy simulations of a
trefoil knot-shaped vortex, inspired by the experiments of Kleckner and Irvine.
The flow parameter space is extended in the present study, including variations
of the circulation Reynolds numbers in the range Re = 2000 - 200000, where Re =
20000 is the value used in the experiments. The vortex line corresponding to
the trefoil knot is defined using a parametric equation and the Biot-Savart law
is employed to initialize the velocity field. The CvP LES computation displays
a good qualitative match with the experiment. In particular, the vortex
entanglement process is accurately represented as well as the subsequent
separation of the main vortex in two distinct structures - a small and a large
vortex - with different self-advection speeds that have been quantified. The
small vortex propagates faster than the large oscillatory vortex which carries
an important amount of vorticity. The advection velocity of the vortex before
bursting is found to be independent of the Reynolds number. The low Reynolds
number computation leads to a decrease of the separated vortices velocity after
bursting, compared to the higher Reynolds computations. The computation of
energy spectra emphasizes intense energy transfers from large to small scales
during the bursting process. The evolution of volume-averaged enstrophy shows
that the bursting leads to the creation of small scales that are sustained a
long time in the flow, when a sufficiently large Reynolds number is considered
(Re>20000). The low Reynolds number case Re = 2000 hinders the generation of
small scales during the bursting process and yields essentially laminar
dynamics. The onset of background turbulence due to the entanglement process
can be observed at Re = 200000
