A Passive particle dispersion control technique was investigated in which longitudinal vortices were injected into a developing coaxial swirling jet with sufficient annular swirl for flow recirculation to occur. Four vortex generators, separated by 90 degrees and placed along the outside of the annular nozzle, injected vorticity opposite in sign to the mean swirl, significantly altering the structure of the swirling jet. The injected vorticity competed with the mean swirl to reduce azimuthal particle flinging and to disrupt the development of the vortex rings in the outer shear layer. Axial flow visualization showed the formation of axial structures at the forcing frequency but considerable azimuthal asymmetry. Horizontal cross sections showed a four-lobed structure which persisted in the natural jet for at least eight inner jet diameters. The particle concentration field was measured using digital processing of pulsed laser sheet images. Outward radial particle dispersion reduced while inward dispersion toward the jet centerline increased indicating that the injected vorticity sufficiently reduced particle flinging by large-scale vortices.

1.
Carletti
M. J.
, and
Rogers
C. B.
,
1994
, “
The Effect of Streamwise Vorticity on Jet Behavior
,”,
Turbulence Control
ASME FED-Vol.
193
, pp.
19
25
.
2.
Carletti, M. J., and Rogers, C. B., and Parekh, D. E., 1993, “The Use of Streamwise Vorticity to Enhance Ejector Performance,” AIAA Shear Flow Conference, AIAA 93-3247.
3.
Ho
C. M.
, and
Gutmark
E.
,
1987
, “
Vortex Induction and Mass Entrainment in a Small-Aspect-Ratio Elliptic Jet
,”
Journal of Fluid Mechanics
, Vol.
179
, pp.
383
405
.
4.
Hussain
F.
, and
Husain
H. S.
,
1989
, “
Elliptic Jets. Part 1. Characteristics of Unexcited and Excited Jets
,”
Journal of Fluid Mechanics
, Vol.
208
, pp.
257
320
.
5.
Kibens, V., and Wlezien, R. W., 1985, “Active Control of Jets from Indeterminate-Origin Nozzles,” AIAA Shear Flow Conference, Boulder, Colorado, AIAA-85-0542.
6.
Longmire
E. K.
, and
Eaton
J. K.
,
1992
, “
Structure of a Particle-Laden Round Jet
,”
Journal of Fluid Mechanics
, Vol.
236
, pp.
217
257
.
7.
Longmire
E. K.
,
Eaton
J. K.
, and
Elkins
C. J.
,
1992
, “
Control of Jet Structure by Crown-Shaped Nozzles
,”
AIAA Journal
, Vol.
30
, No.
2
, pp.
505
512
.
8.
Powell
A.
,
1953
, “
On the Mechanism of Choked Jet Noise
,”
Proceedings of the Physical Society
, London, Sec. B. Vol.
66
, pp.
1039
1056
.
9.
Quinn
W. R.
,
1992
, “
Streamwise Evolution of a Square Jet Cross Section
,”
AIAA Journal
, Vol.
30
, No.
12
, pp.
2852
2857
.
10.
Rogers
C. B.
, and
Parekh
D. E.
,
1994
, “
Mixing Enhancement by and Noise Characteristics of Streamwise Vortices in an Air Jet
,”
AIAA Journal
, Vol.
32
, No.
3
, pp.
464
471
.
11.
Surks, P., Rogers, C. B., and Parekh, D., 1992, “The Effect of Streamwise Vorticity on the Mixing and Acoustic Characteristics of an Air Jet,” Report TR-TF-892, Department of Mechanical Engineering, Tufts University, Medford, MA.
12.
Surks
P.
,
Rogers
C. B.
, and
Parekh
D. E.
,
1994
, “
Entrainment and Acoustic Variations in a Round Jet From Introduced Streamwise Vorticity
,”
AIAA Journal
, Vol.
32
, No.
10
, pp.
2108
2110
.
13.
Tanna
H. K.
,
1977
, “
An Experimental Study of Jet Noise, Part II Shock Associated Noise
,”
Journal of Sound and Vibration
, Vol.
50
, No.
3
, pp.
429
444
.
14.
Wicker, R. B., and Eaton, J. K., 1994, “Structure and Control of a Particle-Laden Coaxial Jet With and Without Annular Swirl,” Report MD-68, Thermosciences Division, Department of Mechanical Engineering, Stanford University.
15.
Wlezien
R. W.
, and
Kibens
V.
,
1986
, “
Passive Control of Jets with Indeterminate Origins
,”
AIAA Journal
, Vol.
24
, No.
8
, pp.
1263
1270
.
16.
Zaman
K. B. M. Q.
,
Reeder
M. F.
, and
Samimy
M.
,
1994
, “
Control of an Axisymmetric Jet Using Vortex Generators
,”
Physics of Fluids
, Vol.
6
, No.
2
, pp.
778
793
.
This content is only available via PDF.
You do not currently have access to this content.