TY - JOUR
T1 - Interactions of a counter-rotating vortex pair at multiple offsets
AU - Forster, Kyle J.
AU - Barber, Tracie J.
AU - Diasinos, Sammy
AU - Doig, Graham
PY - 2017
Y1 - 2017
N2 - The interactions between two streamwise vortices were investigated by wind tunnel testing of two NACA0012 vanes at various lateral offsets. One vane was spaced 10 chord lengths (C) downstream of the other, with both at an angle of incidence of 8 degrees and a Reynolds number of 7×104. The evolution of the vortex pair was observed until 6.5C behind the downstream vane using Particle Image Velocimetry (PIV). It was found that proximity of the upstream vortex to the downstream vane had a significant effect on the rotational rate of the subsequent vortex pair, with far offset cases having little rotation, and near field cases having angle changes of 19.6 degrees per chord length travelled downstream. At the point of vortex impingement on the downstream vane, the rotational rate dropped to near zero due to a significant strength reduction of both vortices. The point of strongest interaction was found to be laterally offset from the point of closest vortex proximity to the downstream vane by −0.15C, with the vortex on the suction side of the vane. In the offset range investigated, a significant instability was observed in only the upstream vortex. These instabilities increased as the proximity between the vortices decreased, peaking where the vortex interaction was strongest.
AB - The interactions between two streamwise vortices were investigated by wind tunnel testing of two NACA0012 vanes at various lateral offsets. One vane was spaced 10 chord lengths (C) downstream of the other, with both at an angle of incidence of 8 degrees and a Reynolds number of 7×104. The evolution of the vortex pair was observed until 6.5C behind the downstream vane using Particle Image Velocimetry (PIV). It was found that proximity of the upstream vortex to the downstream vane had a significant effect on the rotational rate of the subsequent vortex pair, with far offset cases having little rotation, and near field cases having angle changes of 19.6 degrees per chord length travelled downstream. At the point of vortex impingement on the downstream vane, the rotational rate dropped to near zero due to a significant strength reduction of both vortices. The point of strongest interaction was found to be laterally offset from the point of closest vortex proximity to the downstream vane by −0.15C, with the vortex on the suction side of the vane. In the offset range investigated, a significant instability was observed in only the upstream vortex. These instabilities increased as the proximity between the vortices decreased, peaking where the vortex interaction was strongest.
KW - Aerodynamics
KW - Particle Image Velocimetry
KW - Vortex interaction
KW - Streamwise vortices
KW - Counter-rotating vortices
KW - Vortex instability
UR - http://www.scopus.com/inward/record.url?scp=85017119218&partnerID=8YFLogxK
U2 - 10.1016/j.expthermflusci.2017.04.007
DO - 10.1016/j.expthermflusci.2017.04.007
M3 - Article
AN - SCOPUS:85017119218
SN - 0894-1777
VL - 86
SP - 63
EP - 74
JO - Experimental Thermal and Fluid Science
JF - Experimental Thermal and Fluid Science
ER -