Droplets are ubiquitous and have been studied for a century; however, their internal flow pattern and related instabilities that occur in the course of evaporation are not fully understood yet. In this paper, we report our investigation results on an ethanol drop evaporating onto a heated substrate under weightlessness conditions and with a pinned contact line. They have been obtained from both experiments and 3D unsteady computations in order to determine what kind of instabilities develop. Our one-sided model demonstrates quantitative agreement with experiments and confirms that experimentally observed instabilities are driven by thermo-capillary stress and not by the gas convection. Post-processed infrared images drawn from computations led us to conclude that the experimentally observed thermo-convective instabilities, which look very similar to hydrothermal waves in the infrared spectrum, are actually nothing else than unsteady Benard-Marangoni instabilities.

1.
P.
Boulet
,
J.
Tissot
,
F.
Trinquet
, and
L.
Fournaison
,
Appl. Therm. Eng.
50
,
1164
(
2013
).
2.
J.
Chen
,
W.-S.
Liao
,
X.
Chen
,
T.
Yang
,
S. E.
Wark
,
D. H.
Son
,
J. D.
Batteas
, and
P. S.
Cremer
,
ACS Nano
3
,
173
(
2009
).
4.
S. H.
Ko
,
J.
Chung
,
N.
Hotz
,
K. H.
Nam
, and
C. P.
Grigoropoulos
,
J. Micromech. Microeng.
20
,
125010
(
2010
).
5.
N. C.
Schirmer
,
S.
Ströhle
,
M. K.
Tiwari
, and
D.
Poulikakos
,
Adv. Funct. Mater.
21
,
388
(
2010
).
6.
W.
BouZeid
and
D.
Brutin
,
Colloid Surf. A
430
,
1
(
2013
).
7.
W.
BouZeid
,
J.
Vicente
, and
D.
Brutin
,
Colloid Surf. A
432
,
139
(
2013
).
8.
B.
Sobac
and
D.
Brutin
,
Colloid Surf. A
448
,
34
(
2014
).
9.
S.
Dehaeck
,
A.
Rednikov
, and
P.
Colinet
,
Langmuir
30
,
2002
(
2014
).
10.
K.
Sefiane
,
J. R.
Moffat
,
O. K.
Matar
, and
R. V.
Craster
,
Appl. Phys. Lett.
93
,
074103
(
2008
).
11.
K.
Sefiane
,
A.
Steinchen
, and
R.
Moffat
,
Colloid Surf. A
365
,
95
(
2010
).
12.
D.
Brutin
,
Z.-Q.
Zhu
,
O.
Rahli
,
J.-C.
Xie
,
Q.-S.
Liu
, and
L.
Tadrist
,
Microgravity Sci. Technol.
22
,
387
(
2010
).
13.
D.
Brutin
,
B.
Sobac
,
F.
Rigollet
, and
C. L.
Niliot
,
Exp. Therm. Fluid Sci.
35
,
521
(
2011
).
14.
B.
Sobac
and
D.
Brutin
,
Phys. Fluids
24
,
032103
(
2012
).
15.
K.
Sefiane
,
Y.
Fukatani
,
Y.
Takata
, and
J.
Kim
,
Langmuir
29
,
9750
(
2013
).
16.
B.
Sobac
, “
Evaporation de gouttes sessiles: des fluides purs aux fluides complexes
,” Ph.D. thesis,
Aix-Marseille University
,
2012
.
17.
F.
Carle
,
B.
Sobac
, and
D.
Brutin
,
J. Fluid Mech.
712
,
614
(
2012
).
18.
D.
Brutin
,
F.
Carle
, and
F.
Rigollet
, “Radiative heat transfer in droplets,” in
Droplet Wetting and Evaporation
(
Academic Press
,
USA
,
2015
), pp.
193
199
.
19.
M. K.
Smith
and
S. H.
Davis
,
J. Fluid Mech.
132
,
119
(
1983
).
20.
M. K.
Smith
and
S. H.
Davis
,
J. Fluid Mech.
132
,
145
(
1983
).
21.
N.
Garnier
,
A.
Chiffaudel
, and
F.
Daviaud
, “
Hydrothermal waves in a disk of fluid
,” in
Dynamics of Spatio-Temporal Cellular Structures
(
Springer-Verlag
,
New York
,
2006
), p.
147
.
22.
P. J.
Saenz
,
P.
Valluri
,
K.
Sefiane
,
G.
Karapetsas
, and
O. K.
Matar
,
Phys. Fluids
25
,
094101
(
2013
).
23.
D.
Schwabe
,
A.
Zebib
, and
B.-C.
Sim
,
J. Fluid Mech.
491
,
239
(
2003
).
24.
M. K.
Smith
,
Phys. Fluids
29
,
3182
(
1986
).
25.
F. H.
Busse
and
S. C.
Müller
,
Evolution of Spontaneous Structures in Dissipative Continuous Systems
(
Springer Science and Business Media
,
Berlin
,
1998
).
26.
S.
Semenov
,
F.
Carle
,
M.
Medale
, and
D.
Brutin
, “
Boundary conditions for a one-sided numerical model of evaporative instabilities in sessile drops of ethanol on heated substrates
,”
Phys. Rev. E.
(to be published).
27.
R. G.
Picknett
and
R.
Bexon
,
J. Colloid Interf. Sci.
61
,
336
(
1977
).
28.
Y. O.
Popov
,
Phys. Rev. E
71
,
036313
(
2005
).
29.
R. C.
Reid
and
T. K.
Sherwood
,
The Properties of Gases and Liquids
(
McGraw-Hill
,
New York
,
1958
).
30.
M.
Medale
and
P.
Cerisier
,
Eur. Phys. J. Spec. Top.
224
,
217
(
2015
).
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