Effect of 3D Surface Contour on the Flow Field over a Delta Wing*

The flow field over delta-wing aircraft is predominantly influenced by a pair of counter-rotating leading-edge vortices (LEVs). The trajectory of these LEVs can be manipulated by the three-dimensional contour of the wing’s leeward surface. However, the mechanisms behind these vortex trajectories and their consequent effects have not been comprehensively studied. Specifically, the impact of non-uniform surface thickness on the leeside flow field, vortex bursting locations, and secondary vorticity concentrations remains unclear. These factors are critical as they can substantially affect the performance and stability of delta-wing aircraft.

To address these questions, we developed a parametrization of surface shapes that accommodates a broad range of 3D delta wing geometries. Utilizing a high-resolution 3D printer and an innovative compact water tunnel, we initiated an experimental campaign to explore the relationship between surface contour, vortex dynamics, and the overall flow field. The study employs dye visualizations to track LEV locations, paired with stereo particle image velocimetry (SPIV) measurements to capture the flow field in the crossflow plane. Preliminary results indicate notable variations in LEV behavior and secondary flow structures based on surface contour modifications, suggesting potential pathways for optimizing delta-wing design for improved aerodynamic performance.