We investigate the spatial evolution of vorticity dynamics and production mechanisms
of turbulent kinetic energy around a finite NACA 0018 wing with a square wingtip profile
at Rec = 104 and a 10◦ angle of attack with the aid of direct numerical simulation. The
analysis focuses on the highly inhomogeneous region around the tip and the near wake; this
region is highly convoluted, strongly three-dimensional, and far from being self-similar.
The flow separates close to the leading edge creating a large, open recirculation zone
around the central part of the wing. In the proximity of the tip, the flow remains attached
but another smaller recirculation zone forms closer to the trailing edge; this zone strongly
affects the development of the main wing tip vortex. The early formation mechanisms of
three vortices close to the leading edge are elucidated and discussed. More specifically, we
analyze the role of vortex stretching/compression and tilting, and how it affects the strength
of each vortex as it approaches the trailing edge. We find that the three-dimensional
flow separation at the sharp tip close to the trailing edge plays an important role in the
subsequent vortical flow development on the suction side. The production of turbulent
kinetic energy and Reynolds stresses is also investigated and discussed in conjunction with
the identified vortex patterns. The detailed analysis of the mechanisms that sustain vorticity
and turbulent kinetic energy improves our understanding of these highly three-dimensional,
nonequilibrium flows, and it can lead to better actuation methods to manipulate these flows.