A brief review is given on the stability of two-fluid systems. Our interest is primarily driven by drag reduction using superhydrophobic surfaces (SHS) or liquid-infused surfaces (LIS) where the longevity and performance strongly depends on the flow stability. Although the review is limited to immiscible, incompressible, Newtonian fluids with constant properties, the subject is rich in complexity. We focus on three canonical plane parallel flows as part of the general problem: pressure-driven flow, shear-driven flow, and flow down an inclined plane. Based on the linear stability, the flow may become unstable to three modes of instabilities: a Tollmein–Schlichting wave in either the upper fluid layer or the lower fluid layer, and an interfacial mode. These instabilities may be further categorized according to the physical mechanisms that drive them. Particular aspects of weakly nonlinear analyses are also discussed, and some directions for future research are suggested.

References

1.
Weinstein
,
S. J.
, and
Ruschak
,
K. J.
,
2004
, “
Coating Flows
,”
Annu. Rev. Fluid Mech.
,
36
(
1
), pp.
29
53
.
2.
Joseph
,
D. D.
,
Bai
,
R.
,
Chen
,
K. P.
, and
Renardy
,
Y. Y.
,
1997
, “
Core-Annular Flows
,”
Annu. Rev. Fluid Mech.
,
29
(
1
), pp.
65
90
.
3.
Saffman
,
P. G.
, and
Taylor
,
G.
,
1958
, “
The Penetration of a Fluid Into a Porous Medium or a Hele-Shaw Cell Containing a More Viscous Liquid
,”
Proc. R. Soc. A
,
245
(
1242
), pp.
312
329
.
4.
Schrenk
,
W. J.
, and
Alfrey
,
T.
,
1978
, “
Coextruded Multilayer Polymer Films and Sheets
,”
Polymer Blends
, Vol.
2
,
D. R.
Paul
and
N.
Seymour
, eds.,
Academic Press
,
New York
, p.
129
.
5.
Yih
,
C.-S.
,
1990
, “
Wave Formation on a Liquid Layer for De-Icing Airplane Wings
,”
J. Fluid Mech.
,
212
, pp.
41
53
.
6.
Redapangu
,
P. R.
,
Sahu
,
K. C.
, and
Vanka
,
S. P.
,
2013
, “
A Lattice Boltzmann Simulation of Three-Dimensional Displacement Flow of Two Immiscible Liquids in a Square Duct
,”
ASME J. Fluids Eng.
,
135
(
12
), p.
121202
.
7.
Rothstein
,
J. P.
,
2010
, “
Slip on Superhydrophobic Surfaces
,”
Annu. Rev. Fluid Mech.
,
42
(
1
), pp.
89
109
.
8.
Solomon
,
B. R.
,
Khalil
,
K. S.
, and
Varanasi
,
K. K.
,
2014
, “
Drag Reduction Using Lubricant-Impregnated Surfaces in Viscous Laminar Flow
,”
Langmuir
,
30
(
36
), pp.
10970
10976
.
9.
Joseph
,
D. D.
, and
Renardy
,
Y. Y.
,
1993
,
Fundamentals of Two-Fluid Dynamics
,
Springer
,
New York
.
10.
Craster
,
R. V.
, and
Matar
,
O. K.
,
2009
, “
Dynamics and Stability of Thin Liquid Films
,”
Rev. Mod. Phys.
,
81
(
3
), pp.
1131
1198
.
11.
Govindarajan
,
R.
, and
Sahu
,
K. C.
,
2014
, “
Instabilities in Viscosity-Stratified Flow
,”
Annu. Rev. Fluid Mech.
,
46
(
1
), pp.
331
353
.
12.
Timoshin
,
S. N.
,
1997
, “
Instabilities in a High Reynolds-Number Boundary-Layer on a Film Coated Surface
,”
J. Fluid Mech.
,
353
, pp.
163
195
.
13.
Özgen
,
S.
,
Degrez
,
G.
, and
Sarma
,
G. S. R.
,
1998
, “
Two-Fluid Boundary Layer Stability
,”
Phys. Fluids
,
10
(
11
), pp.
2746
2757
.
14.
Timoshin
,
S. N.
, and
Hooper
,
A. P.
,
2000
, “
Mode Coalescence in a Two-Fluid Boundary-Layer Stability Problem
,”
Phys. Fluids
,
12
(
8
), pp.
1969
1978
.
15.
Preziosi
,
L. K.
,
Chen
,
K.
, and
Joseph
,
D. D.
,
1989
, “
Lubricated Pipelining: Stability of Core-Annular Flow
,”
J. Fluid. Mech.
,
201
, pp.
323
356
.
16.
Hu
,
H. H.
, and
Joseph
,
D. D.
,
1989
, “
Lubricated Pipelining: Stability of Core-Annular Flow. Part 2
,”
J. Fluid Mech.
,
205
, pp.
359
396
.
17.
Chen
,
K.
,
Bai
,
R.
, and
Joseph
,
D. D.
,
1990
, “
Lubricated Pipelining. Part 3. Stability of Core-Annular Flow in Vertical Pipes
,”
J. Fluid Mech.
,
214
, pp.
251
286
.
18.
Chen
,
K.
, and
Joseph
,
D. D.
,
1991
, “
Lubricated Pipelining: Stability of Core-Annular Flow. Part 4. Ginzburg-Landau Equations
,”
J. Fluid Mech.
,
227
, pp.
587
615
.
19.
Bai
,
R.
,
Chen
,
K.
, and
Joseph
,
D. D.
,
1992
, “
Lubricated Pipelining: Stability of Core-Annular Flow. Part 5. Experiments and Comparison With Theory
,”
J. Fluid Mech.
,
240
, pp.
97
132
.
20.
Ghosh
,
S.
,
Mandal
,
T. K.
,
Das
,
G.
, and
Das
,
P. K.
,
2009
, “
Review of Oil Water Core Annular Flow
,”
Renewable Sustainable Energy Rev.
,
13
(
8
), pp.
1957
1965
.
21.
Baier
,
G.
, and
Graham
,
M. D.
,
1998
, “
Two-Fluid Taylor–Couette Flow: Experiments and Linear Theory for Immiscible Liquids Between Corotating Cylinders
,”
Phys. Fluids
,
10
(
12
), pp.
3045
3055
.
22.
Baier
,
G.
, and
Graham
,
M. D.
,
2000
, “
Two-Fluid Taylor-Couette Flow With Countercurrent Axial Flow: Linear Theory for Immiscible Liquids Between Corotating Cylinders
,”
Phys. Fluids
,
12
(
2
), pp.
294
303
.
23.
Peng
,
J.
, and
Zhu
,
K. Q.
,
2010
, “
Linear Instability of Two-Fluid Taylor–Couette Flow in the Presence of Surfactant
,”
J. Fluid Mech.
,
651
, pp.
357
385
.
24.
Gelfgat
,
A. Y.
,
Yarin
,
A. L.
, and
Bar-Yoseph
,
P. Z.
,
2001
, “
Three-Dimensional Instability of a Two-Layer Dean Flow
,”
Phys. Fluids
,
13
(
11
), pp.
3185
3195
.
25.
Picardo
,
J. R.
,
Garg
,
P.
, and
Pushpavanam
,
S.
,
2015
, “
Centrifugal Instability of Stratified Two-Phase Flow in a Curved Channel
,”
Phys. Fluids
,
27
(
5
), p.
054106
.
26.
Tzotzi
,
C.
, and
Andritsos
,
N.
,
2013
, “
Interfacial Shear Stress in Wavy Stratified Gas–Liquid Flow in Horizontal Pipes
,”
Int. J. Multiphase Flow
,
54
, pp.
43
54
.
27.
Birvalski
,
M.
,
Tummers
,
M. J.
,
Delfos
,
R.
, and
Henkes
,
R. A. W. M.
,
2014
, “
PIV measurements of waves and turbulence in stratified horizontal two-phase pipe flow
,”
Int. J. Multiphase Flow
,
62
, pp.
161
173
.
28.
Goldstein
,
A.
,
Ullmann
,
A.
, and
Brauner
,
N.
,
2015
, “
Characteristics of Stratified Laminar Flows in Inclined Pipes
,”
Int. J. Multiphase Flow
,
75
, pp.
267
287
.
29.
Sahu
,
K. C.
,
Ding
,
H.
,
Valluri
,
P.
, and
Matar
,
O. K.
,
2009
, “
Linear Stability Analysis and Numerical Simulation of Miscible Two-Layer Channel Flow
,”
Phys. Fluids
,
21
(
4
), p.
042104
.
30.
Ghosh
,
S.
,
Usha
,
R.
, and
Sahu
,
K. C.
,
2014
, “
Linear Stability Analysis of Miscible Two-Fluid Flow in a Channel With Velocity Slip at the Walls
,”
Phys. Fluids
,
26
(
1
), p.
014107
.
31.
Ghosh
,
S.
,
Usha
,
R.
, and
Sahu
,
K. C.
,
2014
, “
Double-Diffusive Two-Fluid Flow in a Slippery Channel: A Linear Stability Analysis
,”
Phys. Fluids
,
26
(
12
), p.
127101
.
32.
Usha
,
R.
,
Tammisola
,
O.
, and
Govindarajan
,
R.
,
2013
, “
Linear Stability of Miscible Two-Fluid Flow Down an Incline
,”
Phys. Fluids
,
25
(
10
), p.
104102
.
33.
Busse
,
A.
,
Sandham
,
N. D.
,
McHale
,
G.
, and
Newton
,
M. I.
,
2013
, “
Change in Drag, Apparent Slip and Optimum Air Layer Thickness for Laminar Flow Over an Idealised Superhydrophobic Surface
,”
J. Fluid Mech.
,
727
, pp.
488
508
.
34.
Wong
,
T.-S.
,
Kang
,
S. H.
,
Tang
,
S. K. Y.
,
Smythe
,
E. J.
,
Hatton
,
B. D.
,
Grinthal
,
A.
, and
Aizenberg
,
J.
,
2011
, “
Bioinspired Self-Repairing Slippery Surfaces With Pressure-Stable Omniphobicity
,”
Nature
,
477
(
7365
), pp.
443
447
.
35.
Rosenberg
,
B. J.
,
Van Buren
,
T.
,
Fu
,
M. K.
, and
Smits
,
A. J.
,
2016
, “
Turbulent Drag Reduction Over Air- and Liquid-Impregnated Surfaces
,”
Phys. Fluids
,
28
(
1
), p.
015103
.
36.
Wexler
,
J. S.
,
Jacobi
,
I.
, and
Stone
,
H. A.
,
2015
, “
Shear-Driven Failure of Liquid-Infused Surfaces
,”
Phys. Rev. Lett.
,
114
(
16
), p.
168301
.
37.
Jacobi
,
I.
,
Wexler
,
J. S.
, and
Stone
,
H. A.
,
2015
, “
Overflow Cascades in Liquid-Infused Substrates
,”
Phys. Fluids
,
27
(
8
), p.
082101
.
38.
Wexler
,
J. S.
,
Grosskopf
,
A.
,
Chow
,
M.
,
Fan
,
Y.
,
Jacobi
,
I.
, and
Stone
,
H. A.
,
2015
, “
Robust Liquid-Infused Surfaces Through Patterned Wettability
,”
Soft Matter
,
11
(
25
), pp.
5023
5029
.
39.
Yih
,
C.-S.
,
1963
, “
Stability of Liquid Flow Down an Inclined Plane
,”
Phys. Fluids
,
6
(
3
), pp.
321
334
.
40.
Yih
,
C.-S.
,
1967
, “
Instability Due to Viscosity Stratification
,”
J. Fluid Mech.
,
27
(
02
), pp.
337
352
.
41.
Hooper
,
A. P.
, and
Boyd
,
W. G. C.
,
1983
, “
Shear-Flow Instability at the Interface Between Two Viscous Fluids
,”
J. Fluid Mech.
,
128
, pp.
507
528
.
42.
Hinch
,
E. J.
,
1984
, “
A Note on the Mechanism of the Instability at the Interface Between Two Shearing Fluids
,”
J. Fluid Mech.
,
144
, pp.
463
465
.
43.
Yiantsios
,
S. G.
, and
Higgins
,
B. G.
,
1988
, “
Linear Stability of Plane Poiseuille Flow of Two Superposed Fluids
,”
Phys. Fluids
,
31
(
11
), pp.
3225
3238
.
44.
Schmid
,
P. J.
, and
Henningson
,
D. S.
,
2001
,
Stability and Transition in Shear Flows
,
Springer
,
New York
.
45.
Malik
,
S. V.
, and
Hooper
,
A. P.
,
2007
, “
Three-Dimensional Disturbances in Channel Flows
,”
Phys. Fluids
,
19
(
5
), p.
052102
.
46.
Boomkamp
,
P. A. M.
, and
Miesen
,
R. H. M.
,
1996
, “
Classification of Instabilities in Parallel Two-Phase Flow
,”
Int. J. Multiphase Flow
,
22
, pp.
67
88
.
47.
Rayleigh
,
L.
,
1882
, “
Investigation of the Character of the Equilibrium of an Incompressible Heavy Fluid of Variable Density
,”
Proc. London Math. Soc.
14
, pp.
170
177
(also Scientific Papers, Vol. II, 1900, Cambridge University Press, Cambridge, pp. 200–207).
48.
Taylor
,
G.
,
1950
, “
The Stability of Liquid Surfaces When Accelerated in a Direction Perpendicular to Their Planes (I)
,”
Proc. R. Soc.
,
201
(
1065
), pp.
192
196
.
49.
Sharp
,
D. H.
,
1984
, “
An Overview of Rayleigh-Taylor Instability
,”
Physica D
,
12
(1–3), pp.
3
18
.
50.
Jacobs
,
J. W.
,
Bunster
,
A.
,
Catton
,
I.
, and
Plesset
,
M. S.
,
1985
, “
Experimental Rayleigh-Taylor Instability in a Circular Tube
,”
ASME J. Fluids Eng.
,
107
(
4
), pp.
460
466
.
51.
Kumar
,
P.
, and
Lal
,
R.
,
2007
, “
On the Stability of Two Superposed Viscous-Viscoelastic (Walters B′) Fluids
,”
ASME J. Fluids Eng.
,
129
(
1
), pp.
116
119
.
52.
Mikaelian
,
K. O.
,
2016
, “
Viscous Rayleigh-Taylor Instability in Spherical Geometry
,”
Phys. Rev. E
,
93
(
2
), p.
023104
.
53.
Miles
,
J. W.
,
1957
, “
On the Generation of Surface Waves by Shear Flows
,”
J. Fluid Mech.
3
(
02
), pp.
185
204
.
54.
Miles
,
J. W.
,
1959
, “
On the Generation of Surface Waves by Shear Flows. Part 2
,”
J. Fluid Mech.
,
6
(
04
), pp.
568
582
.
55.
Young
,
W. R.
, and
Wolfe
,
C. L.
,
2014
, “
Generation of Surface Waves by Shear-Flow Instability
,”
J. Fluid Mech.
,
739
, pp.
276
307
.
56.
Canuto
,
C.
,
Hussaini
,
M. Y.
,
Quarteroni
,
A.
, and
Zang
,
T. A.
,
2006
,
Spectral Methods: Fundamentals in Single Domains
,
Springer
,
New York
.
57.
Orszag
,
S. A.
,
1971
, “
Accurate Solution of the Orr–Sommerfeld Stability Equation
,”
J. Fluid Mech.
,
50
(
04
), pp.
689
703
.
58.
South
,
M. J.
, and
Hooper
,
A. P.
,
1999
, “
Linear Growth in Two-Fluid Plane Poiseuille Flow
,”
J. Fluid Mech.
,
381
, pp.
121
139
.
59.
Malik
,
S. V.
, and
Hooper
,
A. P.
,
2005
Linear Stability and Energy Growth of Viscosity Stratified Flows
,”
Phys. Fluids
,
17
(
2
), p.
024101
.
60.
Kaffel
,
A.
, and
Riaz
,
A.
,
2015
, “
Eigenspectra and Mode Coalescence of Temporal Instability in Two-Phase Channel Flow
,”
Phys. Fluids
,
27
(
4
), p.
042101
.
61.
Hooper
,
A. P.
,
1985
, “
Long-Wave Instability at the Interface Between Two Viscous Fluids: Thin Layer Effects
,”
Phys. Fluids
,
28
(
6
), pp.
1613
1618
.
62.
Shapiro
,
E.
, and
Timoshin
,
S.
,
2005
, “
On the Patterns of Interaction Between Shear and Interfacial Modes in Plane Air-Water Poiseuille Flow
,”
Proc. R. Soc. A
,
461
(
2057
), pp.
1583
1597
.
63.
van Noorden
,
T. L.
,
Boomkamp
,
P. A. M.
,
Knaap
,
M. C.
, and
Verheggen
,
T. M. M.
,
1998
, “
Transient Growth in Parallel Two-Phase Flow: Analogies and Differences With Single Fluid Flow
,”
Phys. Fluids
,
10
(
8
), pp.
2099
2101
.
64.
Yecko
,
P.
, and
Zaleski
,
S.
,
2005
, “
Transient Growth in Two-Phase Mixing Layers
,”
J. Fluid Mech.
528
, pp.
43
52
.
65.
Yecko
,
P.
,
2008
, “
Disturbance Growth in Two-Fluid Channel Flow: The Role of Capillarity
,”
Int. J. Multiphase Flow
,
34
(
3
), pp.
272
282
.
66.
Sahu
,
K. C.
, and
Matar
,
O. K.
,
2011
, “
Three-Dimensional Convective and Absolute Instabilities in Pressure-Driven Two-Layer Channel Flow
,”
Int. J. Multiphase Flow
,
37
(
8
), pp.
987
993
.
67.
Barmak
,
I.
,
Gelfgat
,
A.
,
Vitoshkin
,
H.
,
Ullmann
,
A.
, and
Brauner
,
N.
,
2016
, “
Stability of Stratified Two-Phase Flows in Horizontal Channels
,”
Phys. Fluids
,
28
(
4
), p.
044101
.
68.
Charles
,
M. E.
, and
Lilleleht
,
L. U.
,
1965
, “
An Experimental Investigation of Stability and Interfacial Waves in Co-Current Flow of Two Liquids
,”
J. Fluid Mech.
,
22
(
02
), pp.
217
224
.
69.
Kao
,
T. W.
, and
Park
,
C.
,
1972
, “
Experimental Investigations of the Stability of Channel Flows. Part 2. Two-Layered Co-Current Flow in a Rectangular Channel
,”
J. Fluid Mech.
,
52
(
03
), pp.
401
423
.
70.
Sangalli
,
M.
,
McCready
,
M. J.
, and
Chang
,
H.-C.
,
1997
, “
Stabilization Mechanisms of Short Waves in Stratified Gas-Liquid Flow
,”
Phys. Fluids
,
9
(
4
), pp.
919
939
.
71.
Charru
,
F.
, and
Hinch
,
E. J.
,
2000
, “
‘Phase Diagram’ of Interfacial Instabilities in a Two-Layer Couette Flow and Mechanism of the Long-Wave Instability
,”
J. Fluid Mech.
,
414
, pp.
195
223
.
72.
Hooper
,
A. P.
, and
Boyd
,
W. G. C.
,
1987
, “
Shear-Flow Instability Due to a Wall and a Viscosity Discontinuity at the Interface
,”
J. Fluid Mech.
,
179
, pp.
201
225
.
73.
Barthelet
,
P.
,
Charru
,
F.
, and
Fabre
,
J.
,
1995
, “
Experimental Study of Interfacial Long Waves in a Two-Layer Shear Flow
,”
J. Fluid Mech.
,
303
, pp.
23
53
.
74.
Charru
,
F.
, and
Barthelet
,
P.
,
1999
, “
Secondary Instabilities of Interfacial Waves Due to Coupling With a Long Wave Mode in a Two-Layer Couette Flow
,”
Physica D
,
125
(3–4), pp.
311
324
.
75.
Chin
,
R. W.
,
Abernathy
,
F. H.
, and
Bertschy
,
J. R.
,
1986
, “
Gravity and Shear Wave Stability of Free Surface Flows. Part 1. Numerical Calculations
,”
J. Fluid Mech.
,
168
, pp.
501
513
.
76.
Floryan
,
J. M.
,
Davis
,
S. H.
, and
Kelly
,
R. E.
,
1987
, “
Instabilities of a Liquid Film Flowing Down a Slightly Inclined Plane
,”
Phys. Fluids
,
30
(
4
), pp.
983
989
.
77.
Tilley
,
B. S.
,
Davis
,
S. H.
, and
Bankoff
,
S. G.
,
1994
, “
Linear Stability Theory of Two-Layer Fluid Flow in an Inclined Channel
,”
Phys. Fluids
,
6
(
12
), pp.
3906
3922
.
78.
Camporeale
,
C.
,
Gatti
,
F.
, and
Ridolfi
,
L.
,
2009
, “
Flow Non-Normality-Induced Transient Growth in Superposed Newtonian and Non-Newtonian Fluid Layers
,”
Phys. Rev. E.
,
80
(
3
), p.
036312
.
79.
Floryan
,
J. M.
,
2002
, “
Centrifugal Instability of Couette Flow Over a Wavy Wall
,”
Phys. Fluids
,
14
(
1
), pp.
312
322
.
80.
Szumbarski
,
J.
, and
Floryan
,
J. M.
,
2006
, “
Transient Disturbance Growth in a Corrugated Channel
,”
J. Fluid Mech.
,
568
, pp.
243
272
.
81.
Asai
,
M.
, and
Floryan
,
J. M.
,
2006
, “
Experiments on the Linear Instability of Flow in a Wavy Channel
,”
Eur. J. Mech. B/Fluids
,
25
(
6
), pp.
971
986
.
82.
Moradi
,
H. V.
, and
Floryan
,
J. M.
,
2014
, “
Stability of Flow in a Channel With Longitudinal Grooves
,”
J. Fluid Mech.
,
757
, pp.
613
648
.
83.
Mohammadi
,
A.
,
Moradi
,
H. V.
, and
Floryan
,
J. M.
,
2015
, “
New Instability Mode in a Grooved Channel
,”
J. Fluid Mech.
,
778
, pp.
691
720
.
84.
Mohammadi
,
A.
, and
Floryan
,
J. M.
,
2015
, “
On the Instability of Flow in a Grooved Channel
,”
15th European Turbulence Conference
, Aug. 25–28, Delft, The Netherlands, paper no. 522.
85.
Mohammadi
,
A.
, and
Floryan
,
J. M.
,
2015
, “
Linear Stability Analysis of Flows in a Grooved Channel
,” Bull. Am. Phys. Soc.,
60
(
21
),
68th Annual Meeting of the American Physical Society Division of Fluid Dynamics
, Nov. 22–24, Boston, MA, paper No. BAPS.2015.DFD.R17.2..
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