The role of initial conditions in affecting the evolution toward self-similarity of an axisymmetric turbulent jet is examined. The jet’s near-field coherence was manipulated by non-circular exit geometries of identical open area, , including a square and a fractal exit, for comparison with a classical round orifice jet. Hot-wire anemometry and 2D-planar particle image velocimetry experiments were performed between the exit and a location 26De downstream, where the Reynolds stress profiles are self-similar. This study shows that a fractal geometry significantly changes the near-field structure of the jet, breaking up the large-scale coherent structures, thereby affecting the entrainment rate of the background fluid into the jet stream. It is found that many of the jet’s turbulent characteristics scale with the number of eddy turnover times rather than simply the streamwise coordinate, with the entrainment rate (amongst others) found to be comparable across the different jets after approximately 3-4 eddies have been overturned. The study is concluded by investigating the jet’s evolution toward a self-similar state. No differences are found for the large-scale spreading rate of the jets in the weakly self-similar region, so defined as the region for which some, but not all of the terms of the mean turbulent kinetic energy equation are self-similar. However, the dissipation rate of the turbulent kinetic energy was found to vary more gradually in x than predicted according to the classical equilibrium theories of Kolmogorov. Instead, the dissipation was found to vary in a non-equilibrium fashion for all three jets tested.
REFERENCES
1.
Aleyasin
, S. S.
, Tachie
, M. F.
, and Koupriyanov
, M.
, “PIV measurements in the near and intermediate field regions of jets issuing from eight different nozzle geometries
,” Flow, Turbul. Combust.
99
(2
), 329
–351
(2017
).2.
Antonia
, R. A.
, Browne
, L. W. B.
, Rajagopalan
, S.
, and Chambers
, A. J.
, “On the organized motion of a turbulent plane jet
,” J. Fluid Mech.
134
, 49
–66
(1983
).3.
Antonia
, R. A.
, Chambers
, A. J.
, Britz
, D.
, and Browne
, L. W. B.
, “Organized structures in a turbulent plane jet: Topology and contribution to momentum and heat transport
,” J. Fluid Mech.
172
, 211
–229
(1986
).4.
Antonia
, R. A.
and Zhao
, Q.
, “Effect of initial conditions on a circular jet
,” Exp. Fluids
31
, 319
–323
(2001
).5.
Breda
, M.
and Buxton
, O. R. H.
, “Near and far-field analysis of an axisymmetric fractal-forced turbulent jet
,” in Progress in Turbulence VII
, 1st ed. (Springer
, 2017
), Chap. IV, pp. 211
–217
.6.
Breda
, M.
and Buxton
, O. R. H.
, “Effects of multiscale geometry on the large-scale coherent structures of an axisymmetric turbulent jet
,” J. Visualization
(published online 2018
).7.
Brown
, G. L.
and Roshko
, A.
, “On density effects and large structure in turbulent mixing layers
,” J. Fluid Mech.
64
, 775
–816
(1974
).8.
Burattini
, P.
, Antonia
, R. A.
, and Danaila
, L.
, “Similarity in the far field of a turbulent round jet
,” Phys. Fluids
17
, 025101
(2005a
).9.
Burattini
, P.
, Lavoie
, P.
, and Antonia
, R. A.
, “On the normalized turbulent energy dissipation rate
,” Phys. Fluids
17
, 098103
(2005b
).10.
Buxton
, O. R. H.
, Laizet
, S.
, and Ganapathisubramani
, B.
, “The effects of resolution and noise on kinematic features of fine-scale turbulence
,” Exp. Fluids
51
, 1417
–1437
(2011
).11.
Cafiero
, G.
, Discetti
, S.
, and Astarita
, T.
, “Flow field features of the near-wake of jets with fractal inserts
,” Phys. Fluids
27
, 115103
(2015
).12.
Chao
, J. L.
and Sandborn
, V. A.
, “Evaluation of the momentum equation for a turbulent wall jet
,” J. Fluid Mech.
26
, 819
–828
(1966
).13.
da Silva
, C. B.
, Hunt
, J. C. R.
, Eames
, I.
, and Westerweel
, J.
, “Interfacial layers between regions of different turbulence intensity
,” Annu. Rev. Fluid Mech.
46
(1
), 567
–590
(2014
).14.
Dairay
, T.
, Obligado
, M.
, and Vassilicos
, J. C.
, “Non-equilibrium scaling laws in axisymmetric turbulent wakes
,” J. Fluid Mech.
781
, 166
–195
(2015
).15.
Friehe
, C. A.
, Van Atta
, C. W.
, and Gibson
, C. H.
, “Jet turbulence: Dissipation rate measurements and correlations
,” in Turbulence Shear Flows, AGARD Conference Proceedings
(AGARD
, 1972
), Vol. 93, pp. 1
–7
.16.
Ganapathisubramani
, B.
, Lakshminarasimhan
, K.
, and Clemens
, N. T.
, “Determination of complete velocity gradient tensor by using cinematographic stereoscopic PIV in a turbulent jet
,” Exp. Fluids
42
, 923
–939
(2007
).17.
George
, W. K.
, “The self-preservation of turbulent flows and its relation to initial conditions and coherent structures
,” in Advances in Tubulence
, edited by W. K. George and R. Arndt (Hemisphere
, 1989
), pp 39
–72
.18.
George
, W. K.
and Hussein
, H. J.
, “Locally axisymmetric turbulence
,” J. Fluid Mech.
233
, 1
–23
(1991
).19.
Gibson
, M. M.
, “Spectra of turbulence in a round jet
,” J. Fluid Mech.
15
, 161
–173
(1963
).20.
Goto
, S.
and Vassilicos
, J. C.
, “Energy dissipation and flux laws for unsteady turbulence
,” Phys. Lett. A
379
, 1144
–1148
(2015
).21.
Grinstein
, F. F.
, “Vortex dynamics and entrainment in rectangular free jets
,” J. Fluid Mech.
437
, 69
–101
(2001
).22.
Hearst
, R. J.
and Lavoie
, P.
, “Decay of turbulence generated by a square-fractal-element grid
,” J. Fluid Mech.
741
, 567
–584
(2014
).23.
Hunt
, J. C. R.
, “Atmospheric jets and plumes
,” in Recent Research Advances in the Fluid Mechanics of Turbulent Jets and Plumes
, NATO ASI Series (Series E: Applied Sciences), edited by Davies
, P. A.
and Neves
, M. J. V.
(Springer
, Dordrecht
, 1994
), Vol. 255.24.
Hussein
, H. J.
, Capp
, S. P.
, and George
, W. K.
, “Velocity measurements in a high-Reynolds-number, momentum-conserving, axisymmetric, turbulent jet
,” J. Fluid Mech.
258
, 31
–75
(1994
).25.
Iyogun
, C. O.
and Birouk
, M.
, “Effect of sudden expansion on entrainment and spreading rates of a jet issuing from asymmetric nozzles
,” Flow, Turbul. Combust.
82
, 287
–315
(2009
).26.
Kaminski
, E.
, Tait
, S.
, and Carazzo
, G.
, “Turbulent entrainment in jets with arbitrary buoyancy
,” J. Fluid Mech.
526
, 361
–376
(2005
).27.
Lindgren
, B.
and Johansson
, A. V.
, “Design and evaluation of a low-speed wind-tunnel with expanding corners
,” Technical Report, Royal Institute of Technology
, Stockholm, Sweden
, 2002
.28.
Melina
, G.
, Bruce
, P. J. K.
, and Vassilicos
, J. C.
, “Vortex shedding effects in grid-generated turbulence
,” Phys. Rev. Fluids
1
, 044402
(2016
).29.
Mi
, J.
, Kalt
, P. A. M.
, Nathan
, G. J.
, and Wong
, C. Y.
, “PIV measurements of a turbulent jet issuing from round sharp-edged plate
,” Exp. Fluids
42
, 625
–637
(2007
).30.
Mi
, J.
and Nathan
, G. J.
, “Statistical properties of turbulent free jets issuing from nine differently-shaped nozzles
,” Flow, Turbul. Combust.
84
, 583
–606
(2010
).31.
Mi
, J.
, Nathan
, G. J.
, and Nobes
, D. S.
, “Mixing characteristics of axisymmetric free jets from a contoured nozzle, an orifice plate and a pipe
,” J. Fluids Eng.
123
, 878
–883
(2001
).32.
Mi
, J.
, Xu
, M.
, and Zhou
, T.
, “Reynolds number influence on statistical behaviors of turbulence in a circular free jet
,” Phys. Fluids
25
, 075101
(2013
).33.
Namer
, I.
and Ötügen
, M. V.
, “Velocity measurements in a plane turbulent air jet at moderate Reynolds numbers
,” Exp. Fluids
6
, 387
–399
(1988
).34.
Nedić
, J.
, Ganapathisubramani
, B.
, and Vassilicos
, J. C.
, “Drag and near wake characteristics of flat plates normal to the flow with fractal edge geometries
,” Fluid Dyn. Res.
45
, 061406
(2013a
).35.
Nedić
, J.
, Supponen
, O.
, Ganapathisubramani
, B.
, and Vassilicos
, J. C.
, “Geometrical influence on vortex shedding in turbulent axisymmetric wakes
,” Phys. Fluids
27
, 035103
(2015
).36.
Nedić
, J.
, Vassilicos
, J. C.
, and Ganapathisubramani
, B.
, “Axisymmetric turbulent wakes with new nonequilibrium similarity scalings
,” Phys. Rev. Lett.
111
, 144503
(2013b
).37.
O’Neill
, P. L.
, Nicolaides
, D.
, Honnery
, D.
, and Soria
, J.
, “Autocorrelation functions and the determination of integral length with reference to experimental and numerical data
,” in Proceedings of the 15th Australasian Fluid Mechanics Conference, Sydney, Australia, 13-17 December 2004
, edited by M. Behnia, W. Lin, and G. D. McBain (The University of Sydney
, 2004
).38.
Obligado
, M.
, Dairay
, T.
, and Vassilicos
, J. C.
, “Nonequilibrium scalings of turbulent wakes
,” Phys. Rev. Fluids
1
, 044409
(2016
).39.
Pope
, S. B.
, Turbulent Flows
(Cambridge University Press
, Cambridge
, 2000
).40.
Sadeghi
, H.
, Lavoie
, P.
, and Pollard
, A.
, “Equilibrium similarity solution of the turbulent transport equation along the centreline of a round jet
,” J. Fluid Mech.
772
, 740
–755
(2015
).41.
Shakouchi
, T.
, Iriyama
, S.
, Kawashima
, Y.
, Tsujimoto
, K.
, and Ando
, T.
, “Flow characteristics of submerged free jet flow from petal-shaped nozzle
,” J. Fluid Sci. Technol.
9
(3
), 1
–7
(2014
).42.
Tanaka
, T.
and Eaton
, J. K.
, “A correction method for measuring turbulence kinetic energy dissipation rate by PIV
,” Exp. Fluids
42
, 893
–902
(2007
).43.
Tennekes
, H.
and Lumley
, J. L.
, A First Course in Turbulence
, 1st ed. (MIT Press
, Cambridge, Massachusetts; London
, 1972
).44.
Thiesset
, F.
, Antonia
, R. A.
, and Djenidi
, L.
, “Consequences of self-preservation on the axis of a turbulent round jet
,” J. Fluid Mech.
748
(R2
), 1
–11
(2014
).45.
Townsend
, A. A.
, “The mechanism of entrainment in free turbulent flows
,” J. Fluid Mech.
26
, 689
–715
(1966
).46.
Townsend
, A. A.
, The Structure of Turbulent Shear Flow
, 2nd ed.(Cambridge University Press
, New York
, 1976
).47.
Valente
, P. C.
and Vassilicos
, J. C.
, “Universal dissipation scaling for nonequilibrium turbulence
,” Phys. Rev. Lett.
108
, 214503
(2012
).48.
van Reeuwijk
, M.
and Craske
, J.
, “Energy-consistent entrainment relations for jets and plumes
,” J. Fluid Mech.
782
, 333
–355
(2015
).49.
Vassilicos
, J. C.
, “Dissipation in turbulent flows
,” Annu. Rev. Fluid Mech.
47
, 95
–114
(2015
).50.
Westerweel
, J.
, Fukushima
, C.
, Pedersen
, J. M.
, and Hunt
, J. C. R.
, “Mechanics of the turbulent-nonturbulent interface of a jet
,” Phys. Rev. Lett.
95
, 174501
(2005
).51.
Westerweel
, J.
and Scarano
, F.
, “Universal outlier detection for PIV data
,” Exp. Fluids
39
, 1096
–1100
(2005
).52.
Worth
, N. A.
, Nickels
, T. B.
, and Swaminathan
, N.
, “A tomographic PIV resolution study based on homogeneous isotropic turbulence DNS data
,” Exp. Fluids
49
, 637
–656
(2010
).53.
Wygnanski
, I.
, Champagne
, F. H.
, and Marasli
, B.
, “On the large-scale structures in two-dimensional, small-deficit, turbulent wakes
,” J. Fluid Mech.
168
, 31
–71
(1986
).54.
Xu
, M.
, Pollard
, A.
, Mi
, J.
, Secretain
, F.
, and Sadeghi
, H.
, “Effects of Reynolds number on some properties of a turbulent jet from a long square pipe
,” Phys. Fluids
25
, 035102
(2013
).55.
Xu
, M. Y.
, Tong
, X. Q.
, Yue
, D. T.
, Zhang
, J. P.
, Mi
, J. C.
, Nathan
, G. J.
, and Kalt
, P. A.
, “Effect of noncircular orifice plates on the near flow field of turbulent free jets
,” Chin. Phys. B
23
, 124703
(2014
).56.
Yule
, A. J.
, “Large-scale structure in the mixing layer of a round jet
,” J. Fluid Mech.
89
(3
), 413
–433
(1978
).© 2018 Author(s).
2018
Author(s)
You do not currently have access to this content.
