Effect of sweep angle on wing-strake vortex — Interaction and breakdown over double delta wings

The lifting surface of present-day aircrafts cruising at high speeds is often delta wings or a variant in order to enhance lift and maneuverability. These aircrafts are most vulnerable to accidents during take-off and landing because of the danger of abrupt loss in lift due to vortex-breakdown at high angles of attack on the top-surface. In particular, a double delta wing experiences the vortex-breakdown phenomenon that is further complicated by the wing-strake vortex-interaction. We attempt to gain insight into the wing-strake vortex-interaction and vortexbreakdown phenomenon using a two-pronged approach: Windtunnel experiments and numerical simulations of two models of the double delta wing having same apex angle but different wing sweep angle. The pressure distribution on the upper surface of the wing at varying angles of attack is reported and compared to numerical simulations to glean substantive data on the physical mechanism. We also identify the location of vortex breakdown from pressure distribution for both the models.