Influence of leading edge shapes on vortex behaviour of delta wing

This paper analyzes the vortex behaviour of three delta wing configurations namely plane delta wing, saw-tooth delta wing, and sinusoidal tooth delta wing. Experiments such as flow visualization at low speeds, oil flow visualization at different velocities are performed using a low speed wind tunnel. Experiments are conducted for different Reynolds number 0.25, 0.3 and 0.35 million at various angles of attack 10° to 40° in steps of 10°. CFD studies are also carried out by using commercially available software ANSYS FLUENT to have an insight of unsteady nature of vortices. Oil flow visualization study depicts two symmetric separation lines indicating symmetric vortices for all three delta wings at 10° and 20° angles of attack. It was also noticed that at 30° angle of attack plane delta shows asymmetric separation lines indicating asymmetric nature of vortices. Again at 40° angle of attack random pattern of oil traces are evident of flow separation and wake formation on the top surface of the wing. Plane delta has more area of random pattern compared to sinusoidal-tooth and saw-tooth delta wing. Results were authenticated with computational study and it is found that vortices are highly stable at 10° and 20° angles of attack for all planforms. At the same time vortices are found to be flipflopping if angle of attack is increased to 30°, which in turns are governed by unsteady forces due to uneven pressure distribution.