Influences of angle of attack, Reynolds number and leading edge bluntness on inner vortex characterization of blunt-edged VFE-2 delta wing

Purpose The purpose of this study is to investigate the flow on blunt-edged delta wing Vortex Flow Experiment (VFE-2) configuration in wind tunnel testing. The flow characteristics of this wing exhibits differently from sharp-edges where the primary vortex developed at certain chord-wise position from the wing apex. Design/methodology/approach A model of VFE-2 wing has been replicated with the main chord length of 1.3 meters with two sets of leading-edge radius. The experiments were performed in Universiti Teknologi Malaysia wind tunnel sized of 2 × 1.5 m 2 test section with maximum speeds of 80 m/s. To investigate the effects of leading-edge radius, Reynolds number and angle of attack, the experiments were carried out at 1 × 10 6 and 2 × 10 6 Reynolds number based on mean aerodynamic chord length. Three measurement techniques were used on the wing, i.e. flow visualization, surface and off-surface pressure measurement. Findings This study has observed that the inner vortex has first developed inboard of the wing at low angle of attack. At moderate angle of attacks, the primary vortex is then developed in the leading-edge region, at the same time, the inner vortex also well-developed inboard of the wing. When the angle of attacks is further increased, primary vortex becomes very prominent in the leading edge and the inner vortex has disappeared. Originality/value The research results provide a better understanding into the effects of angle of attacks, Reynolds number and leading-edge bluntness on delta wing flow topology, particularly the interaction between the primary vortex and the inner vortex.