We investigate theoretically the buoyancy-driven motion of a viscous drop in a yield-stress material, incorporating elastic effects represented by the Saramito–Herschel–Bulkley constitutive equation. We solve the governing equations using an open-source finite volume solver and utilizing the volume of fluid technique to accurately capture the interface between the two fluids. To validate our numerical approach, we compare our results with data from previous experimental and numerical studies. We find quantitative agreement in terms of terminal velocities and drop shapes, affirming the accuracy of our model and its numerical solution. Notably, we observe that incorporating elastic effects into the modeling of the continuous phase is essential for predicting phenomena reported in experiments, such as the inversion of the flow field behind the sedimenting drop (i.e., the negative wake) or the formation of a teardrop shape. Due to the elastoviscoplastic nature of the continuous phase, we observe that small drops remain entrapped because the buoyancy force is insufficient to fluidize the surrounding material. We investigate entrapment conditions using two different protocols, which yield different outcomes due to the interplay between capillarity and elastoplasticity. Finally, we conduct an extensive parametric analysis to evaluate the impact of rheological parameters (yield stress, elastic modulus, and interfacial tension) on the dynamics of sedimentation.

1.
Bonn
,
D.
,
M. M.
Denn
,
L.
Berthier
,
T.
Divoux
, and
S.
Manneville
, “
Yield stress materials in soft condensed matter
,”
Rev. Mod. Phys.
89
(
3
),
1
40
(
2017
).
2.
Bingham
,
E. C.
,
Fluidity and Plasticity
(
McGraw-Hill
,
1922
).
3.
Herschel
,
W. H.
, and
R.
Bulkley
, “
Konsistenzmessungen von Gummi-Benzollösungen.: Kolloid-Zeitschrift
,”
Kolloid-Z.
39
,
291
300
(
1926
).
4.
Varges
,
P. R.
,
C. M.
Costa
,
B. S.
Fonseca
,
M. F.
Naccache
, and
P.
De Souza Mendes
, “
Rheological characterization of Carbopol® dispersions in water and in water/glycerol solutions
,”
Fluids
4
(
1
),
3
(
2019
).
5.
Papanastasiou
,
T. C.
, “
Flows of materials with yield
,”
J. Rheol.
31
(
5
),
385
404
(
1987
).
6.
Bercovier
,
M.
, and
M.
Engelman
, “
A finite-element method for incompressible non-Newtonian flows
,”
J. Comput. Phys.
36
(
3
),
313
326
(
1980
).
7.
Glowinski
,
R.
, and
P.
Le Tallec
,
Augmented Lagrangian and Operator-Splitting Methods in Nonlinear Mechanics
, SIAM Studies in Applied Mathematics Vol. 9 (Society for Applied Mathematics, Philadelphia, 1989).
8.
Moschopoulos
,
P.
,
S.
Varchanis
,
A.
Syrakos
,
Y.
Dimakopoulos
, and
J.
Tsamopoulos
, “
S-PAL: A stabilized finite element formulation for computing viscoplastic flows
,”
J. Non-Newtonian Fluid Mech.
309
,
104883
(
2022
).
9.
Dimakopoulos
,
Y.
,
G.
Makrigiorgos
,
G. C.
Georgiou
, and
J.
Tsamopoulos
, “
The PAL (penalized augmented Lagrangian) method for computing viscoplastic flows: A new fast converging scheme
,”
J. Non-Newtonian Fluid Mech.
256
(
March
),
23
41
(
2018
).
10.
Oldroyd
,
J. G.
, “
Two-dimensional plastic flow of a Bingham solid: A plastic boundary-layer theory for slow motion
,”
Math. Proc. Cambridge Philos. Soc.
43
(
3
),
383
395
(
1947
).
11.
Mitsoulis
,
E.
, and
J.
Tsamopoulos
, “
Numerical simulations of complex yield-stress fluid flows
,”
Rheol. Acta
56
(
3
),
231
258
(
2017
).
12.
Frigaard
,
I.
, “
Simple yield stress fluids
,”
Curr. Opin. Colloid Interface Sci.
43
,
80
93
(
2019
).
13.
de Cagny
,
H.
,
M.
Fazilati
,
M.
Habibi
,
M. M.
Denn
, and
D.
Bonn
, “
The yield normal stress
,”
J. Rheol.
63
(
2
),
285
290
(
2019
).
14.
Holenberg
,
Y.
,
O. M.
Lavrenteva
,
U.
Shavit
, and
A.
Nir
, “
Particle tracking velocimetry and particle image velocimetry study of the slow motion of rough and smooth solid spheres in a yield-stress fluid
,”
Phys. Rev. E
86
(
6
),
066301
(
2012
).
15.
Beris
,
A. N.
,
J. A.
Tsamopoulos
,
R. C.
Armstrong
, and
R. A.
Brown
, “
Creeping motion of a sphere through a Bingham plastic
,”
J. Fluid Mech.
158
,
219
244
(
1985
).
16.
Fraggedakis
,
D.
,
Y.
Dimakopoulos
, and
J.
Tsamopoulos
, “
Yielding the yield-stress analysis: A study focused on the effects of elasticity on the settling of a single spherical particle in simple yield-stress fluids
,”
Soft Matter
12
(
24
),
5378
5401
(
2016
).
17.
Mougin
,
N.
,
A.
Magnin
, and
J.-M.
Piau
, “
The significant influence of internal stresses on the dynamics of bubbles in a yield stress fluid
,”
J. Non-Newtonian Fluid Mech.
171–172
,
42
55
(
2012
).
18.
Liu
,
Y. J.
,
T. Y.
Liao
, and
D. D.
Joseph
, “
A two-dimensional cusp at the trailing edge of an air bubble rising in a viscoelastic liquid
,”
J. Fluid Mech.
304
,
321
342
(
1995
).
19.
Pilz
,
C.
, and
G.
Brenn
, “
On the critical bubble volume at the rise velocity jump discontinuity in viscoelastic liquids
,”
J. Non-Newtonian Fluid Mech.
145
(
2–3
),
124
138
(
2007
).
20.
Dubash
,
N.
, and
I. A.
Frigaard
, “
Propagation and stopping of air bubbles in Carbopol solutions
,”
J. Non-Newtonian Fluid Mech.
142
(
1–3
),
123
134
(
2007
).
21.
Tsamopoulos
,
J.
,
Y.
Dimakopoulos
,
N.
Chatzidai
,
G.
Karapetsas
, and
M.
Pavlidis
, “
Steady bubble rise and deformation in Newtonian and viscoplastic fluids and conditions for bubble entrapment
,”
J. Fluid Mech.
601
,
123
164
(
2008
).
22.
Dimakopoulos
,
Y.
,
M.
Pavlidis
, and
J.
Tsamopoulos
, “
Steady bubble rise in Herschel-Bulkley fluids and comparison of predictions via the augmented Lagrangian method with those via the Papanastasiou model
,”
J. Non-Newtonian Fluid Mech.
200
,
34
51
(
2013
).
23.
Lopez
,
W. F.
,
M. F.
Naccache
, and
P. R.
de Souza Mendes
, “
Rising bubbles in yield stress materials
,”
J. Rheol.
62
(
1
),
209
219
(
2018
).
24.
Pourzahedi
,
A.
,
M.
Zare
, and
I. A.
Frigaard
, “
Eliminating injection and memory effects in bubble rise experiments within yield stress fluids
,”
J. Non-Newtonian Fluid Mech.
292
(
November 2020
),
104531
(
2021
).
25.
Saramito
,
P.
, “
A new constitutive equation for elastoviscoplastic fluid flows
,”
J. Non-Newtonian Fluid Mech.
145
(
1
),
1
14
(
2007
).
26.
Mises
,
R. V.
, “
Mechanik der festen Körper im plastisch- deformablen Zustand
,”
Nachr. Ges. Wiss. Göttingen, Math. Klasse
1913
,
582
592
(
1913
).
27.
Saramito
,
P.
, “
A new elastoviscoplastic model based on the Herschel-Bulkley viscoplastic model
,”
J. Non-Newtonian Fluid Mech.
158
(
1–3
),
154
161
(
2009
).
28.
Tripathi
,
M. K.
,
K. C.
Sahu
, and
R.
Govindarajan
, “
Dynamics of an initially spherical bubble rising in quiescent liquid
,”
Nat. Commun.
6
,
6268
(
2015
).
29.
Fraggedakis
,
D.
,
M.
Pavlidis
,
Y.
Dimakopoulos
, and
J.
Tsamopoulos
, “
On the velocity discontinuity at a critical volume of a bubble rising in a viscoelastic fluid
,”
J. Fluid Mech.
789
,
310
346
(
2016
).
30.
Moschopoulos
,
P.
,
A.
Spyridakis
,
S.
Varchanis
,
Y.
Dimakopoulos
, and
J.
Tsamopoulos
, “
The concept of elasto-visco-plasticity and its application to a bubble rising in yield stress fluids
,”
J. Non-Newtonian Fluid Mech.
297
(
November
), 104670 (2021).
31.
Varchanis
,
S.
,
A.
Syrakos
,
Y.
Dimakopoulos
, and
J.
Tsamopoulos
, “
A new finite element formulation for viscoelastic flows: Circumventing simultaneously the LBB condition and the high-Weissenberg number problem
,”
J. Non-Newtonian Fluid Mech.
267
(
December 2018
),
78
97
(
2019
).
32.
Varchanis
,
S.
,
A.
Syrakos
,
Y.
Dimakopoulos
, and
J.
Tsamopoulos
, “
PEGAFEM-V: A new Petrov-Galerkin finite element method for free surface viscoelastic flows
,”
J. Non-Newtonian Fluid Mech.
284
(
August
),
104365
(
2020
).
33.
Varchanis
,
S.
,
D.
Pettas
,
Y.
Dimakopoulos
, and
J.
Tsamopoulos
, “
Origin of the sharkskin instability: Nonlinear dynamics
,”
Phys. Rev. Lett.
127
(
8
),
088001
(
2021
).
34.
Holenberg
,
Y.
,
O. M.
Lavrenteva
, and
A.
Nir
, “
Interaction of viscous drops in a yield stress material
,”
Rheol. Acta
50
(
4
),
375
387
(
2011
).
35.
Lavrenteva
,
O. M.
,
Y.
Holenberg
, and
A.
Nir
, “
Motion of viscous drops in tubes filled with yield stress fluid
,”
Chem. Eng. Sci.
64
(
22
),
4772
4786
(
2009
).
36.
Holenberg
,
Y.
,
O. M.
Lavrenteva
,
A.
Liberzon
,
U.
Shavit
, and
A.
Nir
, “
PTV and PIV study of the motion of viscous drops in yield stress material
,”
J. Non-Newtonian Fluid Mech.
193
,
129
143
(
2013
).
37.
Potapov
,
A.
,
R.
Spivak
,
O. M.
Lavrenteva
, and
A.
Nir
, “
Motion and deformation of drops in Bingham fluid
,”
Ind. Eng. Chem. Res.
45
(
21
),
6985
6995
(
2006
).
38.
Brackbill
,
J. U.
,
D. B.
Kothe
, and
C.
Zemach
, “
A continuum method for modeling surface tension
,”
J. Comput. Phys.
100
(
2
),
335
354
(
1992
).
39.
Dimakopoulos
,
Y.
, and
J.
Tsamopoulos
, “
Transient displacement of Newtonian and viscoplastic liquids by air in complex tubes
,”
J. Non-Newtonian Fluid Mech.
142
(
1–3
),
162
182
(
2007
).
40.
Boger
,
D. V.
,
D. U.
Hur
, and
R. J.
Binnington
, “
Further observations of elastic effects in tubular entry flows
,”
J. Non-Newtonian Fluid Mech.
20
,
31
49
(
1986
).
41.
Manglik
,
R. M.
,
V. M.
Wasekar
, and
J.
Zhang
, “
Dynamic and equilibrium surface tension of aqueous surfactant and polymeric solutions
,”
Exp. Therm. Fluid Sci.
25
(
1–2
),
55
64
(
2001
).
42.
Popinet
,
S.
, “
A quadtree-adaptive multigrid solver for the Serre–Green–Naghdi equations
,”
J. Comput. Phys.
302
,
336
358
(
2015
).
43.
Berny
,
A.
,
L.
Deike
,
T.
Séon
, and
S.
Popinet
, “
Role of all jet drops in mass transfer from bursting bubbles
,”
Phys. Rev. Fluids
5
(
3
),
33605
(
2020
).
44.
López-Herrera
,
J. M.
,
S.
Popinet
, and
A. A.
Castrejón-Pita
, “
An adaptive solver for viscoelastic incompressible two-phase problems applied to the study of the splashing of weakly viscoelastic droplets
,”
J. Non-Newtonian Fluid Mech.
264
,
144
158
(
2019
).
45.
Turkoz
,
E.
,
J. M.
Lopez-Herrera
,
J.
Eggers
,
C. B.
Arnold
, and
L.
Deike
, “
Axisymmetric simulation of viscoelastic filament thinning with the Oldroyd-B model
,”
J. Fluid Mech.
851
,
R2
(
2018
).
46.
Fattal
,
R.
, and
R.
Kupferman
, “
Constitutive laws for the matrix-logarithm of the conformation tensor
,”
J. Non-Newtonian Fluid Mech.
123
(
2–3
),
281
285
(
2004
).
47.
Popinet
,
S.
, “
Gerris: A tree-based adaptive solver for the incompressible Euler equations in complex geometries
,”
J. Comput. Phys.
190
(
2
),
572
600
(
2003
).
48.
Brown
,
D. L.
,
R.
Cortez
, and
M. L.
Minion
, “
Accurate projection methods for the incompressible Navier–Stokes equations
,”
J. Comput. Phys.
168
(
2
),
464
499
(
2001
).
49.
Deshpande
,
S. S.
,
L.
Anumolu
, and
M. F.
Trujillo
, “
Evaluating the performance of the two-phase flow solver interFoam
,”
Comput. Sci. Discov.
5
(
1
),
014016
(
2012
).
50.
Harlen
,
O. G.
, “
The negative wake behind a sphere sedimenting through a viscoelastic fluid
,”
J. Non-Newtonian Fluid Mech.
108
(
1–3
),
411
430
(
2002
).
51.
Esposito
,
G.
,
Y.
Dimakopoulos
, and
J.
Tsamopoulos
, “
Buoyancy driven flow of a viscous drop in viscoelastic materials
,”
J. Non-Newtonian Fluid Mech.
321
,
105124
(
2023
).
52.
Singh
,
J. P.
, and
M. M.
Denn
, “
Interacting two-dimensional bubbles and droplets in a yield-stress fluid
,”
Phys. Fluids
20
(
4
) (
2008
).
53.
Edgeworth
,
R.
,
B. J.
Dalton
, and
T.
Parnell
, “
The pitch drop experiment
,”
Eur. J. Phys.
5
(
4
),
198
200
(
1984
).
54.
Abbasi Yazdi
,
A.
, and
G.
D’Avino
, “
Sedimentation of a spheroidal particle in an elastoviscoplastic fluid
,”
Phys. Fluids
36
(
4
),
43119
(
2024
).
55.
Kordalis
,
A.
,
S.
Varchanis
,
G.
Ioannou
,
Y.
Dimakopoulos
, and
J.
Tsamopoulos
, “
Investigation of the extensional properties of elasto-visco-plastic materials in cross-slot geometries
,”
J. Non-Newtonian Fluid Mech.
296
(
January
),
104627
(
2021
).
56.
Kordalis
,
A.
,
D.
Pema
,
S.
Androulakis
,
Y.
Dimakopoulos
, and
J.
Tsamopoulos
, “
Hydrodynamic interaction between coaxially rising bubbles in elastoviscoplastic materials: Equal bubbles
,”
Phys. Rev. Fluids
8
(
8
),
1
33
(
2023
).
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