  High-fidelity simulations are conducted to investigate the turbulent boundary
layers around a finite-span NACA0012 wing with a rounded wing-tip geometry at a
chord-based Reynolds number of $Re_c=200\,000$ and at various angles of attack
up to $10^\circ$. The study aims to discern the differences between the
boundary layers on the finite-span wing and those on infinite-span wings at
equivalent angles of attack. The finite-span boundary layers exhibit: (i) an
altered streamwise and a non-zero spanwise pressure gradient as a result of the
variable downwash induced by the wing-tip vortices (an inviscid effect typical
of finite-span wings); (ii) differences in the flow history at different
wall-normal distances, caused by the variable flow angle in the wall-normal
direction (due to constant pressure gradients and variable momentum normal to
the wall); (iii) laminar flow entrainment into the turbulent boundary layers
near the wing tip (due to a laminar/turbulent interface); and (iv) variations
in boundary layer thickness across the span, attributed to the variable
wall-normal velocity in that direction (a primarily inviscid effect). These
physical effects are then used to explain the differences in the Reynolds
stress profiles and other boundary layer quantities, including the reduced
near-wall peak of the streamwise Reynolds stress and the elevated Reynolds
stress levels near the boundary layer edge, both observed in the finite-span
wings. Other aspects of the flow, such as the downstream development of
wing-tip vortices and their interactions with the surrounding flow, are
reserved for future investigations.
