  While tapered swept wings are widely used, the influence of taper on their
post-stall wake characteristics remains largely unexplored. To address this
issue, we conduct an extensive study using direct numerical simulations to
characterize the wing taper and sweep effects on laminar separated wakes. We
analyze flows behind NACA 0015 cross-sectional profile wings at post-stall
angles of attack $\alpha=14^\circ$--$22^\circ$ with taper ratios
$\lambda=0.27$--$1$, leading edge sweep angles $0^\circ$--$50^\circ$, and semi
aspect ratios $sAR =1$ and $2$ at a mean-chord-based Reynolds number of $600$.
Tapered wings have smaller tip chord length, which generates a weaker tip
vortex, and attenuates inboard downwash. This results in the development of
unsteadiness over a large portion of the wingspan at high angles of attack. For
tapered wings with backward-swept leading edges unsteadiness emerges near the
wing tip. On the other hand, wings with forward-swept trailing edges are shown
to concentrate wake shedding structures near the wing root. For highly swept
untapered wings, the wake is steady, while unsteady shedding vortices appear
near the tip for tapered wings with high leading edge sweep angles. For such
wings, larger wake oscillations emerge near the root as the taper ratio
decreases. While the combination of taper and sweep increases flow
unsteadiness, we find that tapered swept wings have more enhanced aerodynamic
performance than untapered and unswept wings, exhibiting higher time-averaged
lift and lift-to-drag ratio. The current findings shed light on the fundamental
aspects of flow separation over tapered wings in the absence of turbulent flow
effects.

Fluid Dynamics