Laminar flow separation over tapered wings, Part 1: a computational study

As the first part of our three-way study, we comprehensively characterize the effects of wing taper on laminar flows over NACA 0015 wings at post-stall angles of attack using direct numerical simulations. With a straight leading edge, the wing is tapered by sweeping the trailing edge forward. The flows over such wings generally concentrate unsteadiness towards the wing root. For a straight trailing edge, tapering is analyzed with a backward swept leading edge. Over these wings, vortical structures are advected towards the wing tip. The reduced wing tip chord length of tapered wings constrains the formation of the tip vortex, reducing its strength and streamwise length. We also show how unsteadiness appears over wings with a high leading edge sweep angle. As wings with high sweep angles are tapered, shedding develops near the wing tip. Furthermore, we characterize the effect of tapering on the aerodynamic forces over the wing. We show that tapered wings increase lift with leading-edge sweep, in contrast to untapered wings. The current results provide insights into the effect of wing taper on wake dynamics and support future studies on flow separation over tapered wings at higher Reynolds numbers.