  The interaction between a vortex and an impacting body which is oriented
normally to it is complex due to the interaction of inviscid and viscous
three-dimensional mechanisms. To model this process, direct numerical
simulations of a thin cylinder intersecting a columnar vortex oriented normally
to it are conducted. By varying the impact parameter and the Reynolds number,
the two regimes of interaction mentioned in the literature are distinguished:
the weak and strong vortex regimes. Low impact parameters, representing strong
vortices, led to ejection and interaction of secondary vorticity from the
cylinder's boundary layer, while high impact parameters, representing weak
vortices, led to approximately inviscid interaction of the cylinder with the
primary vortex through deformations. No significant effect of the Reynolds
number in the overall phenomenology is found, even if larger Reynolds numbers
lead to the formation of increasingly smaller and more intense vortex
structures in the parameter range studied. Finally, the hydrodynamic force
curves on the cylinder are analyzed, showing that intense forces could be
locally generated for some parameter regimes, but that the average force on the
cylinder does not substantially deviate from baseline cases where no vortex was
present. Our results shed light on the underlying mechanisms of vortex-body
interactions and their dependence on various parameters.
