The quasi-stable sheet cavitation produced in a small Venturi channel is investigated using a fast synchrotron x-ray imaging technique aided with conventional high speed photography. The use of x rays instead of visible light solves cavitation opacity related issues, and x-ray phase contrast-based edge enhancement enables high-definition visualization of the internal two-phase morphology. The simultaneous acquisition of time-resolved velocity and void fraction fields through post-processing of the recorded x-ray images reveals, for the first time, the complex diphasic flow structures inside the sheet cavity, which is essentially divided into six characteristic parts. Distinct from the current mainstream view, the globally steady sheet cavitation is found to be characterized by a weak but constantly existing re-entrant flow that can penetrate the entire cavity. The turbulent velocity fluctuations inside the sheet cavity are also investigated. The turbulence level in the reverse flow region is observed to be as low as in the outer main flow, demonstrating the relatively steady status of the re-entrant flow. Unlike the streamwise and cross-stream fluctuations, the shear stress appears to be weakly correlated with the velocity gradient. The collapse of the vapor phase and the vaporization at the upstream cavity interface are found to be the primary causes of shear stress intensification.

1.
V.
Aeschlimann
,
S.
Barre
, and
H.
Djeridi
, “
Velocity field analysis in an experimental cavitating mixing layer
,”
Phys. Fluids
23
(
5
),
055105
(
2011
).
2.
V.
Aeschlimann
,
S.
Barre
, and
S.
Legoupil
, “
X-ray attenuation measurements in a cavitating mixing layer for instantaneous two-dimensional void ratio determination
,”
Phys. Fluids
23
(
5
),
055101
(
2011
).
3.
S.
Barre
,
J.
Rolland
,
G.
Boitel
,
E.
Goncalves
, and
R. F.
Patella
, “
Experiments and modeling of cavitating flows in Venturi: Attached sheet cavitation
,”
Eur. J. Mech. B: Fluids
28
(
3
),
444
464
(
2009
).
4.
J. K.
Bothell
,
N.
Machicoane
,
D.
Li
,
T. B.
Morgan
, and
T. J.
Heindel
, “Comparison
of X-ray and optical measurements in the near-field of an optically dense coaxial air-assisted atomizer
,”
Int. J. Multiphase Flow
125
,
103219
(
2020
).
5.
B.
Budich
,
S. J.
Schmidt
, and
N. A.
Adams
, “
Numerical simulation and analysis of condensation shocks in cavitating flow
,”
J. Fluid Mech.
838
,
759
813
(
2018
).
6.
M.
Callenaere
,
J.-P.
Franc
,
J.-M.
Michel
, and
M.
Riondet
, “
The cavitation instability induced by the development of a re-entrant jet
,”
J. Fluid Mech.
444
,
223
256
(
2001
).
7.
J.
Canny
, “
A computational approach to edge detection
,”
IEEE Trans.
6
,
679
698
(
1986
).
8.
O.
Coutier-Delgosha
,
J.-F.
Devillers
,
T.
Pichon
,
A.
Vabre
,
R.
Woo
, and
S.
Legoupil
, “
Internal structure and dynamics of sheet cavitation
,”
Phys. Fluids
18
(
1
),
017103
(
2006
).
9.
O.
Coutier-Delgosha
,
B.
Stutz
,
A.
Vabre
, and
S.
Legoupil
, “
Analysis of cavitating flow structure by experimental and numerical investigations
,”
J. Fluid Mech.
578
,
171
222
(
2007
).
10.
O.
Coutier-Delgosha
,
A.
Vabre
,
M.
Hocevar
,
R.
Delion
,
A.
Dazin
,
D.
Lazaro
, and
W. K.
Lee
, “
Local measurements in cavitating flow by ultra-fast x-ray imaging
,” in
ASME 2009 Fluids Engineering Division Summer Meeting
(
ASME
,
2009
), pp.
371
379
.
11.
A.
Danlos
,
F.
Ravelet
,
O.
Coutier-Delgosha
, and
F.
Bakir
, “
Cavitation regime detection through proper orthogonal decomposition: Dynamics analysis of the sheet cavity on a grooved convergent–divergent nozzle
,”
Int. J. Heat Fluid Flow
47
,
9
20
(
2014
).
12.
M.
Dular
,
B.
Bachert
,
B.
Stoffel
, and
B.
Širok
, “
Relationship between cavitation structures and cavitation damage
,”
Wear
257
,
1176
1184
(
2004
).
13.
E. J.
Foeth
,
C. W. H.
Van Doorne
,
T.
Van Terwisga
, and
B.
Wieneke
, “
Time resolved PIV and flow visualization of 3D sheet cavitation
,”
Exp. Fluids
40
(
4
),
503
513
(
2006
).
14.
H.
Ganesh
,
S. A.
Mäkiharju
, and
S. L.
Ceccio
, “
Bubbly shock propagation as a mechanism for sheet-to-cloud transition of partial cavities
,”
J. Fluid Mech.
802
,
37
78
(
2016
).
15.
M.
Gembicky
,
D.
Oss
,
R.
Fuchs
, and
P.
Coppens
, “
A fast mechanical shutter for submicrosecond time-resolved synchrotron experiments
,”
J. Synchrotron Radiat.
12
(
5
),
665
669
(
2005
).
16.
S.
Gopalan
and
J.
Katz
, “
Flow structure and modeling issues in the closure region of attached cavitation
,”
Phys. Fluids
12
(
4
),
895
911
(
2000
).
17.
T. J.
Heindel
, “
A review of X-ray flow visualization with applications to multiphase flows
,”
J. Fluids Eng.
133
(
7
),
074001
(
2011
).
18.
T. J.
Heindel
, “
X-ray imaging techniques to quantify spray characteristics in the near-field
,”
Atomization Sprays
28
(
11
),
1029
1059
(
2018
).
19.
K.-S.
Im
,
K.
Fezzaa
,
Y. J.
Wang
,
X.
Liu
,
J.
Wang
, and
M.-C.
Lai
, “
Particle tracking velocimetry using fast x-ray phase-contrast imaging
,”
Appl. Phys. Lett.
90
(
9
),
091919
(
2007
).
20.
C. O.
Iyer
and
S. L.
Ceccio
, “
The influence of developed cavitation on the flow of a turbulent shear layer
,”
Phys. Fluids
14
(
10
),
3414
3431
(
2002
).
21.
I. K.
Karathanassis
,
P.
Koukouvinis
,
E.
Kontolatis
,
Z.
Lee
,
J.
Wang
,
N.
Mitroglou
, and
M.
Gavaises
, “
High-speed visualization of vortical cavitation using synchrotron radiation
,”
J. Fluid Mech.
838
,
148
164
(
2018
).
22.
A.
Kastengren
and
C. F.
Powell
, “
Synchrotron X-ray techniques for fluid dynamics
,”
Exp. Fluids
55
,
1686
(
2014
).
23.
Y.
Kawanami
,
H.
Kato
,
H.
Yamaguchi
,
M.
Tanimura
, and
Y.
Tagaya
, “
Mechanism and control of cloud cavitation
,”
J. Fluids Eng.
119
(
4
),
788
794
(
1997
).
24.
I.
Khlifa
,
A.
Vabre
,
M.
Hočevar
,
K.
Fezzaa
,
S.
Fuzier
,
O.
Roussette
, and
O.
Coutier-Delgosha
, “
Fast x-ray imaging of cavitating flows
,”
Exp. Fluids
58
(
11
),
157
(
2017
).
25.
R. T.
Knapp
, “
Recent investigations of the mechanics of cavitation and cavitation damage
,”
Trans. ASME
77
,
1045
1054
(
1955
).
26.
A. Y.
Kravtsova
,
D. M.
Markovich
,
K. S.
Pervunin
,
M. V.
Timoshevskiy
, and
K.
Hanjalić
, “
High-speed visualization and PIV measurements of cavitating flows around a semi-circular leading-edge flat plate and NACA0015 hydrofoil
,”
Int. J. Multiphase Flow
60
,
119
134
(
2014
).
27.
K. R.
Laberteaux
and
S. L.
Ceccio
, “
Partial cavity flows. Part 1. Cavities forming on models without spanwise variation
,”
J. Fluid Mech.
431
,
1
41
(
2001
).
28.
Q.
Le
,
J. P.
Franc
, and
J. M.
Michel
, “
Partial cavities: Global behavior and mean pressure distribution
,”
J. Fluids Eng.
115
,
243
248
(
1993
).
29.
S.-J.
Lee
and
G.-B.
Kim
, “
X-ray particle image velocimetry for measuring quantitative flow information inside opaque objects
,”
J. Appl. Phys.
94
(
5
),
3620
3623
(
2003
).
30.
J.-B.
Leroux
,
J. A.
Astolfi
, and
J. Y.
Billard
, “
An experimental study of unsteady partial cavitation
,”
J. Fluids Eng.
126
(
1
),
94
101
(
2004
).
31.
X.
Long
,
J.
Zhang
,
J.
Wang
,
M.
Xu
, and
B.
Ji
, “
Experimental investigation of the global cavitation dynamic behavior in a Venturi tube with special emphasis on the cavity length variation
,”
Int. J. Multiphase Flow
89
,
290
298
(
2016
).
32.
P. F.
Pelz
,
T.
Keil
, and
T. F.
Groß
, “
The transition from sheet to cloud cavitation
,”
J. Fluid Mech.
817
,
439
454
(
2017
).
33.
T. M.
Pham
,
F.
Larrarte
, and
D. H.
Fruman
, “
Investigation of unsteady sheet cavitation and cloud cavitation mechanisms
,”
J. Fluids Eng.
121
(
2
),
289
296
(
1999
).
34.
C.
Poelma
, “
Measurement in opaque flows: A review of measurement techniques for dispersed multiphase flows
,”
Acta Mech.
231
(
6
),
2089
2111
(
2020
).
35.
S.
Prothin
,
J. Y.
Billard
, and
H.
Djeridi
, “
Image processing using proper orthogonal and dynamic mode decompositions for the study of cavitation developing on a NACA0015 foil
,”
Exp. Fluids
57
(
10
),
157
(
2016
).
36.
G. H.
Schnerr
and
J.
Sauer
, “
Physical and numerical modeling of unsteady cavitation dynamics
,” in
Fourth International Conference on Multiphase Flow
,
New Orleans, USA
,
2001
.
37.
A. K.
Singhal
,
M. M.
Athavale
, and
H.
Li
, “
Mathematical basis and validation of the full cavitation model
,”
J. Fluid Eng.
124
,
617
624
(
2002
).
38.
B.
Stutz
and
J. L.
Reboud
, “
Two-phase flow structure of sheet cavitation
,”
Phys. Fluids
9
(
12
),
3678
3686
(
1997
).
39.
B.
Stutz
and
J.-L.
Reboud
, “
Measurements within unsteady cavitation
,”
Exp. Fluids
29
(
6
),
545
552
(
2000
).
40.
B.
Stutz
and
S.
Legoupil
, “
X-ray measurements within unsteady cavitation
,”
Exp. Fluids
35
(
2
),
130
138
(
2003
).
41.
Y.
Wang
,
X.
Liu
,
K.-S.
Im
,
W.-K.
Lee
,
J.
Wang
,
K.
Fezzaa
, and
J. R.
Winkelman
, “
Ultrafast X-ray study of dense-liquid-jet flow dynamics using structure-tracking velocimetry
,”
Nat. Phys.
4
(
4
),
305
(
2008
).
42.
J.
Wu
,
H.
Ganesh
, and
S.
Ceccio
, “
Multimodal partial cavity shedding on a two-dimensional hydrofoil and its relation to the presence of bubbly shocks
,”
Exp. Fluids
60
(
4
),
66
(
2019
).
43.
H.
Zhang
,
Z.
Zuo
,
K. A.
Mørch
, and
S.
Liu
, “
Thermodynamic effects on Venturi cavitation characteristics
,”
Phys. Fluids
31
,
097107
(
2019
).
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