The present experimental study investigated the synthetic jet flow characteristics issued from four different orifice shapes (Re = 4739–5588). The flow dynamics of the jet is examined using the particle image velocimetry technique for circular, rectangular, square, and elliptical orifice shapes and two different surface spacings (z/d = 3 and 8). The results are presented in terms of streamwise distribution of velocity, normal stress, and shear stress. Furthermore, the most dominant modes of higher energy containing structures are obtained using proper orthogonal decomposition and compared for different orifice shapes. The results show that for a lower nozzle to surface spacing, vortices formed in the wall jet from the elliptical orifice contain higher energy than the other orifice shapes. The higher energy-containing vortices cause a delay in attaining self-similarity. Therefore, the self-similarity in the wall jet for the elliptical orifice is delayed than that of the other orifice shapes. Also, the elliptical orifice shape has relatively higher normal and shear stresses than that of other orifice shapes. The elliptical orifice shows 30% and 17% higher crosswise normal and shear stress than that of the circular orifice, respectively. However, for the larger nozzle to surface spacing, the least dominant mode of the structure is observed for the rectangular orifice shape, which results in a shifting of the self-similarity location toward the stagnation point. The findings from the present work are used to explain the variation of the heat transfer rate from a synthetic jet having different orifice shapes and impinging at different surface spacings.

1.
Arshad
,
A.
,
Jabbal
,
M.
, and
Yan
,
Y.
, “
Synthetic jet actuators for heat transfer enhancement–A critical review
,”
Int. J. Heat Mass Transfer
146
,
118815
(
2020
).
2.
Bhapkar
,
U.
,
Mohanan
,
S.
,
Agrawal
,
A.
, and
Srivastava
,
A.
, “
Interferometry based whole-field measurements of an impinging turbulent synthetic jet
,”
Int. Commun. Heat Mass Transfer
58
,
118
124
(
2014a
).
3.
Bhapkar
,
U.
,
Srivastava
,
A.
, and
Agrawal
,
A.
, “
Acoustic and heat transfer aspects of an inclined impinging synthetic jet
,”
Int. J. Therm. Sci.
74
,
145
155
(
2013
).
4.
Bhapkar
,
U. S.
,
Srivastava
,
A.
, and
Agrawal
,
A.
, “
Acoustic and heat transfer characteristics of an impinging elliptical synthetic jet generated by acoustic actuator
,”
Int. J. Heat Mass Transfer
79
,
12
23
(
2014b
).
5.
Bhapkar
,
U. S.
,
Yadav
,
H.
, and
Agrawal
,
A.
, “
PIV study of radial wall jet formed by a normally impinging turbulent synthetic jet
,”
J. Flow Vis. Image Proc.
26
(
2
),
99
(
2019
).
6.
Cater
,
J. E.
, and
Soria
,
J.
, “
The evolution of round zero-net-mass-flux jets
,”
J. Fluid Mech.
472
,
167
200
(
2002
).
7.
Chaudhari
,
M.
,
Puranik
,
B.
, and
Agrawal
,
A.
, “
Effect of orifice shape in synthetic jet based impingement cooling
,”
Exp. Therm. Fluid Sci.
34
(
2
),
246
256
(
2010a
).
8.
Chaudhari
,
M.
,
Puranik
,
B. P.
, and
Agrawal
,
A.
, “
Heat transfer analysis in a rectangular duct without and with cross-flow and an impinging synthetic jet
,”
IEEE Trans. Comp. Packag. Technol.
33
,
488
497
(
2010b
).
9.
Chaudhari
,
M.
,
Verma
,
G.
,
Puranik
,
B.
, and
Agrawal
,
A.
, “
Frequency response of a synthetic jet cavity
,”
Exp. Therm. Fluid Sci.
33
(
3
),
439
448
2009
).
10.
Coleman
,
H.
, and
Steele
,
W.
,
Experimentation, Validation and Uncertainty Analysis for Engineers
(
John Wiley and Sons
,
New York
,
2009
).
11.
Fukiba
,
K.
,
Ota
,
K.
, and
Harashina
,
Y.
, “
Heat transfer enhancement of a heated cylinder with synthetic jet impingement from multiple orifices
,”
Int. Commun. Heat Mass Transfer
99
,
1
6
(
2018
).
12.
Ghaffari
,
O.
,
Solovitz
,
S.
, and
Arik
,
M.
, “
An investigation into flow and heat transfer for a slot impinging synthetic jet
,”
Int. J. Heat Mass Transfer
100
,
634
645
(
2016
).
13.
Glezer
,
A.
, and
Amitay
,
M.
, “
Synthetic jets
,”
Annu. Rev. Fluid Mech.
34
(
1
),
503
529
(
2002
).
14.
Greco
,
C. S.
,
Paolillo
,
G.
,
Ianiro
,
A.
,
Cardone
,
G.
, and
de Luca
,
L.
, “
Effects of the stroke length and nozzle-to-plate distance on synthetic jet impingement heat transfer
,”
Int. J. Heat Mass Transfer
117
,
1019
1031
(
2018
).
15.
Gutmark
,
E.
, and
Ho
,
C.
, “
Visualisation of a forced elliptic jet
,”
AIAA J.
24
,
684
685
(
1986
).
16.
Gutmark
,
E. J.
, and
Grinstein
,
F. F.
, “
Flow control with noncircular jets
,”
Annu. Rev. Fluid Mech.
31
(
1
),
239
272
(
1999
).
17.
Hashiehbaf
,
A.
, and
Romano
,
G.
, “
Particle image velocimetry investigation of mixing enhancement of non-circular shape edge nozzles
,”
Int. J. Heat Fluid Flow
44
,
208
221
(
2013
).
18.
Hong
,
M. H.
,
Cheng
,
S. Y.
, and
Zhong
,
S.
, “
Effect of geometric parameters on synthetic jet: A review
,”
Phys. Fluids
32
(
3
),
031301
(
2020
).
19.
Hussain
,
F.
, and
Hussain
,
H.
, “
Elliptic jets. Part I. Characteristics of unexcited and excited jets
,”
J. Fluid Mech.
208
,
257
320
(
1989
).
20.
Joshi
,
A.
, “
PIV for air and its applications for synthetic jet
,” M.Tech. thesis (
Department of Mechanical Engineering, I.I.T
.,
Bombay
,
2015
).
21.
Krishan
,
G.
,
Aw
,
K. C.
, and
Sharma
,
R. N.
, “
Comparison of the flow-field characteristics of a slot synthetic jet with and without sidewalls
,”
Int. J. Heat Fluid Flow
82
,
108535
(
2020
).
22.
Kumar
,
A.
,
Saha
,
A. K.
,
Panigrahi
,
P. K.
, and
Karn
,
A.
, “
On the flow physics and vortex behavior of rectangular orifice synthetic jets
,”
Exp. Therm. Fluid Sci.
103
,
163
181
(
2019
).
23.
Lee
,
J.
, and
Lee
,
S.
, “
The effect of nozzle aspect ratio on stagnation region heat transfer characteristics of elliptic impinging jet
,”
Int. J. Heat Mass Transfer
43
,
555
575
(
2000
).
24.
Mane
,
P.
,
Mossi
,
K.
,
Rostami
,
A.
,
Bryant
,
R.
, and
Castro
,
N.
, “
Piezoelectric actuators as synthetic jets: Cavity dimension effects
,”
J. Intell. Mater. Syst. Struct.
18
(
11
),
1175
1190
(
2007
).
25.
Mangate
,
L.
, and
Chaudhari
,
M.
, “
Heat transfer and acoustic study of impinging synthetic jet using diamond and oval shape orifice
,”
Int. J. Therm. Sci.
89
,
100
109
(
2015
).
26.
Mangate
,
L.
,
Yadav
,
H.
,
Agrawal
,
A.
, and
Chaudhari
,
M.
, “
Experimental investigation on thermal and flow characteristics of synthetic jet with multiple-orifice of different shapes
,”
Int. J. Therm. Sci.
140
,
344
357
(
2019
).
27.
Maria
,
G.
,
Cicca
,
D.
, and
Iuso
,
G.
, “
On the near field of an axisymmetric synthetic jet
,”
Fluid Dyn. Res.
39
,
673
693
(
2007
).
28.
Michalke
,
A.
, “
Instability of a compressible circular free jet with consideration of the influence of the jet boundary layer thickness
,” Report No. NASA-TM-75190,
1977
.
29.
Miller
,
R.
, “
Numerical simulation of non-circular jets
,”
Comput. Fluids
24
(
1
),
1
25
(
1995
).
30.
Mishra
,
A.
,
Djenidi
,
L.
, and
Agrawal
,
A.
, “
Dynamics of wall jet flow under external pulsation
,”
Phys. Fluids
33
,
095103
(
2021
).
31.
Murugan
,
T.
,
Deyashi
,
M.
,
Dey
,
S.
,
Rana
,
S. C.
, and
Chatterjee
,
P. K.
, “
Recent developments on synthetic jets
,”
Defence Sci. J.
66
(
5
),
489
498
(
2016
).
32.
Paolillo
,
G.
,
Greco
,
C. S.
, and
Cardone
,
G.
, “
The evolution of quadruple synthetic jets
,”
Exp. Therm. Fluid Sci.
89
,
259
(
2017
).
33.
Quinn
,
W.
, “
On mixing in a turbulent free jet
,”
Phys. Fluids A
1
(
10
),
1716
1721
(
1989
).
34.
Quinn
,
W.
, “
Experimental study of the near field and transition region of a free jet issuing from a sharp edged elliptic orifice plate
,”
Eur. J. Mech. Fluids
26
,
583
614
(
2007
).
35.
Quinn
,
W.
, and
Militzer
,
J.
, “
Experimental and numerical study of a turbulent free square jet
,”
Phys. Fluids
31
(
5
),
1017
1025
(
1988
).
36.
Raffel
,
M.
,
Willert
,
C.
, and
Kompenhans
,
J.
,
Particle Image Velocimetry: A Practical Guide
(
Springer-Verlag
,
Berlin
,
1998
).
37.
Sharma
,
P.
,
Singh
,
P.
,
Sahu
,
S.
, and
Yadav
,
H.
, “
A critical review on flow and heat transfer characteristics of synthetic jet
,”
Trans. Indian Natl. Acad. Eng.
7
,
61
92
(
2022
).
38.
Silva-Llanca
,
L.
, and
Ortega
,
A.
, “
Vortex dynamics and mechanisms of heat transfer enhancement in synthetic jet impingement
,”
Int. J. Therm. Sci.
112
,
153
164
(
2017
).
39.
Singh
,
P. K.
,
Sahu
,
S. K.
,
Upadhyay
,
P. K.
, and
Jain
,
A. K.
, “
Experimental investigation on thermal characteristics of hot surface by synthetic jet impingement
,”
Appl. Therm. Eng.
165
,
114596
(
2020
).
40.
Walimbe
,
P.
,
Agrawal
,
A.
, and
Chaudhari
,
M. B.
, “
Flow characteristics and novel applications of synthetic jets—A review
,”
J. Heat Transfer
(published online) (
2021
).
41.
Wang
,
L.
,
Feng
,
L. H.
,
Wang
,
J. J.
, and
Li
,
T.
, “
Characteristics and mechanism of mixing enhancement for noncircular synthetic jets at low Reynolds number
,”
Exp. Therm. Fluid Sci.
98
,
731
743
(
2018
).
43.
Yadav
,
H.
, and
Agrawal
,
A.
, “
Self-similar behavior of turbulent impinging jet based upon outer scaling and dynamics of secondary peak in heat transfer
,”
Int. J. Heat Fluid Flow
72
,
123
142
(
2018a
).
44.
Yadav
,
H.
, and
Agrawal
,
A.
, “
Effect of vortical structures on velocity and turbulent fields in the near region of an impinging turbulent jet
,”
Phys. Fluids
30
(
3
),
035107
(
2018b
).
42.
Yadav
,
H.
,
Joshi
,
A.
,
Chaudhari
,
M.
, and
Agrawal
,
A.
, “
An experimental study of a multi-orifice synthetic jet with application to cooling of compact devices
,”
AIP Adv.
9
(
12
),
125108
(
2019
).
45.
Yan
,
W.
,
Mei
,
S.
,
Liu
,
H.
,
Soong
,
C.
, and
Yang
,
W.
, “
Measurement of detailed heat transfer on a surface under arrays of impinging elliptic jets by a transient liquid crystal technique
,”
Int. J. Heat Mass Transfer
47
,
5235
5245
(
2004
).
46.
Zaman
,
K.
, “
Spreading characteristics of compressible jets from nozzles of various geometries
,”
J. Fluid Mech.
383
,
197
228
(
1999
).
You do not currently have access to this content.