Leading Edge Vortex Analysis
The first feature of the leading edge vortex can be summarised from wall shear stress coefficient curves of angles of attack 2˚ to 4˚ in curved plate part. The small variations of the wall shear stress coefficients indicate the reattachment point and separation point are stable. So this proves the steadiness of the leading edge vortex as the vortex is formed through flow separation and reattachment.
The second feature of the leading edge vortex is that it increases in size as the angle of attack increases. The three detailed figures of the leading edge vortex are shown above at angle of attack 2˚, 3˚ and 4˚ respectively. For curved plate at angle of attack 2 degrees, the leading edge vortex covers 10% of the chord length as the flow turns backward and reattaches at 10% of the chord length (see Figure 1). When the angle of attack increases to 3 degrees, the leading edge vortex increases in size and covers 22% of the chord length (see Figure 2). For angle of attack 4 degrees, the length becomes 40% of the chord length (see Figure 3).
Also, it is worth noticing that the leading edge vortex is shedding when the angle of attack exceeds 4 degrees. That means the increasing of angle of attack may finally leads to the vortex shedding.
The second feature of the leading edge vortex is that it increases in size as the angle of attack increases. The three detailed figures of the leading edge vortex are shown above at angle of attack 2˚, 3˚ and 4˚ respectively. For curved plate at angle of attack 2 degrees, the leading edge vortex covers 10% of the chord length as the flow turns backward and reattaches at 10% of the chord length (see Figure 1). When the angle of attack increases to 3 degrees, the leading edge vortex increases in size and covers 22% of the chord length (see Figure 2). For angle of attack 4 degrees, the length becomes 40% of the chord length (see Figure 3).
Also, it is worth noticing that the leading edge vortex is shedding when the angle of attack exceeds 4 degrees. That means the increasing of angle of attack may finally leads to the vortex shedding.