This paper studies the effect of perturbation to the breakdown of the leading-edge vortices over delta wings. The passive perturbation in the normal direction is achieved by installing the hemisphere-like bulges on the delta wing along the projection of the vortices. The key purpose of this perturbation is to delay or suppress vortex breakdown over delta wings according to the self-induction mechanism theory. The design of bulge-like surface for delta wings offers a minimization of initial vorticity gradient and an elimination of linearly mutual induction within the vortex core. Three delta wings with swept angles of 60°, 65dg and 70° have been used. Dye flow visualization and force measurement in different water tunnels are performed at the water speed of U=0.10, 0.15, 0.20 and 0.25 m/s. In flow visualization, the results show contributions of bulges as perturbation to leading-edge vortices. The best outcome of perturbing the vortex core occurs in the case of the 65° delta wing. The breakdown positions on the 65° delta wing are delayed in almost the entire range of angles of attack, and that, the results are presented here.
[1]
Petter Krus,et al.
Flow visualisation and force and moment correlations in a water tunnel
,
2003
.
[2]
A. Leonard.
Vortex methods for flow simulation
,
1980
.
[3]
W. Althaus,et al.
Breakdown of Slender Vortices
,
1995
.
[4]
Thomas McLaughlin,et al.
Control of vortex breakdown on a delta wing by periodic blowing and suction
,
1999
.
[5]
N J Wood,et al.
An experimental investigation of twin fin buffeting and suppression
,
1993
.
[6]
Sutthiphong Srigrarom,et al.
Surface Shaping to Suppress Vortex Breakdown on Delta Wings
,
2000
.
[7]
M. Kurosaka,et al.
Shaping of Delta-Wing Planform to Suppress Vortex Breakdown
,
2000
.
[8]
Y. Shmyglevskii,et al.
On “vortex breakdown”
,
1995
.