Flow visualization of 3D separation on a plane rectangular wing
 |
| ● | Partially tripped flow - Stall cell growth with alpha |
In the pictures below the AR2.0, Re 1.0 partially tripped case is presented. The outer red line shows the area the stall cell occupied at every angle. It should be noted that these are snapshots from the videos that were filmed during the tests. Watching the filmed cases a tuft would be considered "belonging to a SC" if it would deviate from the chordwise flow most of the time during a run. We had 30" long videos for the partially tripped cases. This was enough as, even though the flow was unsteady, it was stable, i.e. the flow structure would remain the same.
This was not the case for the free transition and fully tripped flow cases, where the number and/or position of the vortical structures could change even after 60". Similar findings have been reported in the past by (Gregory, et al., 1971). On occasions even a "half SC" would form at the wing tips, i.e. only one vortex structure next to the fence forming a "full SC" with the mirror vortex due to the fence wall.
This was not the case for the free transition and fully tripped flow cases, where the number and/or position of the vortical structures could change even after 60". Similar findings have been reported in the past by (Gregory, et al., 1971). On occasions even a "half SC" would form at the wing tips, i.e. only one vortex structure next to the fence forming a "full SC" with the mirror vortex due to the fence wall.
AR 2.0, Re 1.0, a 8.0 tripped at midspan
AR 2.0, Re 1.0, a 7.0 tripped at midspan
AR 2.0, Re 1.0, a 9.0 tripped at midspan
AR 2.0, Re 1.0, a 10.0 tripped at midspan
AR 2.0, Re 1.0, a 11.0 tripped at midspan
AR 2.0, Re 1.0, a 12.0 tripped at midspan
 |
Stable case