Reynolds number effects on the vortical-flow structure generated by a double-delta wing

An experimental investigation of the high-incidence vortical flowfield over a 76/40 degrees double-delta wing model with sharp leading edges was condu cted in the Naval Postgraduate School water tunnel facility at three nomina l flow Reynolds numbers of 15000, 45000, and 75000 (based on centerline cho rd). Extensive flow visualization studies were performed with the dye-injec tion technique, followed by laser Doppler velocity measurements. The primar y objective of this investigation was the determination of the influence of Reynolds number on vortex interactions/trajectories, and breakdown. It was found that there is a significant influence of Reynolds number. Specifical ly, with the increase of flow Reynolds number the strake and wing vortex tr ajectories tend to move outboards and closer to the model surface, and the vortex breakdown location moves forwards toward the apex of the model. The intertwining or coiling-up feature of the vortex interaction phenomenon bec omes less dominant and disappears altogether at high Reynolds numbers. Thes e trends in the vortex interaction and bursting data are found to be in goo d agreement with previous wind tunnel data.