Numerical simulations are performed to investigate the characteristics of peristaltic flow in a model stomach during the mixing and digestion process. The geometrical model for the stomach consists of an axisymmetric tube of varying diameter with a wall at one end, representing the antrum and closed pylorus. The antral contraction waves (ACWs) that produce the peristaltic flow are modeled as traveling waves that deform the boundary and consequently the computational mesh. This geometrical model is implemented into the open source code OpenFOAM. A parametric study is performed in which the fluid viscosity, wave speed, wave width, and maximum relative occlusion are varied. The effect of these parameters on the retropulsive jet induced near the pylorus and the recirculation between pairs of consecutive ACWs is investigated. Both of these flow features contribute to the mixing and digestion process. The retropulsive jet is quantified by its peak velocity and length along the centerline. For each wave geometry, these quantities are found to be independent of the Reynolds number for low Reynolds numbers, while for Reynolds numbers exceeding one, the peak centerline velocity decreases and the jet length increases as the Reynolds number increases. Moreover, the velocity and pressure curves are found to scale with the wave speed at low Reynolds numbers. Between different wave geometries, scaling laws are proposed and tested for the peak centerline velocity and jet length. Particle tracking and vorticity plots show that mixing efficiency increases when the relative occlusion increases, as well as when the viscosity or wave width decreases.

1.
K.
Ullah
and
N.
Ali
, “
Stability and bifurcation analysis of stagnation/equilibrium points for peristaltic transport in a curved channel
,”
Phys. Fluids
31
,
073103
(
2019
).
2.
Y.
Aboelkassem
, “
Pumping flow model in a microchannel with propagative rhythmic membrane contraction
,”
Phys. Fluids
31
,
051902
(
2019
).
3.
S.
Alokaily
,
K.
Feigl
,
F.
Tanner
, and
E.
Windhab
, “
Numerical simulations of the transport of Newtonian and non-Newtonian fluids via peristaltic motion
,”
Appl. Rheol.
28
,
32832
(
2018
).
4.
W.
Choi
,
J.
Park
,
H.
Byeon
, and
S.
Lee
, “
Flow characteristics around a deformable stenosis under pulsatile flow condition
,”
Phys. Fluids
30
,
011902
(
2018
).
5.
G.
Shit
and
N.
Ranjit
, “
Role of slip velocity on peristaltic transport of couple stress fluid through an asymmetric non-uniform channel: Application to digestive system
,”
J. Mol. Liq.
221
,
305
315
(
2016
).
6.
A.
Bandopadhyay
,
D.
Tripathi
, and
S.
Chakraborty
, “
Electroosmosis-modulated peristaltic transport in microfluidic channels
,”
Phys. Fluids
28
,
052002
(
2016
).
7.
D.
Tripathi
and
O. A.
Bég
, “
A study on peristaltic flow of nano fluids: Application in drug delivery systems
,”
Int. J. Heat Mass Transfer
70
,
61
70
(
2014
).
8.
D.
Soybel
, “
Anatomy and physiology of the stomach
,”
Surg. Clin. North Am.
85
,
875
894
(
2005
).
9.
K.
Schulze
, “
Imaging and modeling of digestion in the stomach and the duodenum
,”
Neurogastroenterol. Motil.
18
,
172
183
(
2006
).
10.
W.
Cannon
, “
Movements of the stomach, studied by means of the Röntgen rays
,”
J. Boston Soc. Med. Sci.
2
,
59
66
(
1898
).
11.
K.
Kelly
, “
Gastric emptying of liquids and solids: Roles of proximal and distal stomach
,”
Am. J. Physiol.: Gastrointest. Liver Physiol.
239
,
G71
G76
(
1980
).
12.
J.
Urbain
,
E. V.
Cutsem
,
J.
Siegel
,
S.
Mayeur
,
A.
Vandecruys
,
J.
Janssens
,
M. D.
Roo
, and
G.
Vantrappen
, “
Visualization and characterization of gastric contractions using a radionuclide technique
,”
Am. J. Physiol.: Gastrointest. Liver Physiol.
259
,
G1062
G1067
(
1990
).
13.
A.
Pal
,
J.
Brasseur
, and
B.
Abrahamsson
, “
A stomach road or “Magenstrasse” for gastric emptying
,”
J. Biomech.
40
,
1202
1210
(
2007
).
14.
F.
Kong
and
R.
Singh
, “
A model stomach system to investigate disintegration kinetics of solid foods during gastric digestion
,”
J. Food Sci.
73
,
E202
E210
(
2008
).
15.
Y.
Imai
,
I.
Kobayashi
,
S.
Ishida
,
T.
Ishikawa
,
M.
Buist
, and
T.
Yamaguchi
, “
Antral recirculation in the stomach during gastric mixing
,”
Am. J. Physiol.: Gastrointest. Liver Physiol.
304
,
G536
G542
(
2013
).
16.
N.
Pallotta
,
M.
Cicala
,
C.
Frandina
, and
E.
Corazziari
, “
Antro-pyloric contractile patterns and transpyloric flow after meal ingestion in humans
,”
Am. J. Gastroenterol.
93
,
2513
2522
(
1998
).
17.
K.
Indireshkumar
,
J.
Brasseur
,
H.
Faas
,
G.
Hebbard
,
P.
Kunz
,
J.
Dent
,
C.
Feinle
,
M.
Li
,
P.
Boesiger
,
M.
Fried
, and
W.
Schwizer
, “
Relative contributions of “pressure pump” and “peristaltic pump” to gastric emptying
,”
Am. J. Physiol.: Gastrointest. Liver Physiol.
278
,
G604
G616
(
2000
).
18.
M.
Kwiatek
,
A.
Steingoetter
,
A.
Pal
,
D.
Menne
,
J.
Brasseur
,
G.
Hebbard
,
P.
Boesiger
,
M.
Thumshirn
,
M.
Fried
, and
W.
Schwizer
, “
Quantification of distal antral contractile motility in healthy human stomach with magnetic resonance imaging
,”
J. Magn. Reson. Imaging
24
,
1101
1109
(
2006
).
19.
S.
Aoki
,
K.
Uesugi
,
H.
Ozawa
, and
M.
Kayano
, “
Evaluation of the correlation between in vivo and in vitro release of phenylpropanolamine HCl from controlled-release tablets
,”
Int. J. Pharm.
85
,
65
73
(
1992
).
20.
S.
Aoki
,
H.
Ando
,
K.
Tatsuishi
,
K.
Uesugi
, and
H.
Ozawa
, “
Determination of the mechanical impact force in the in vitro dissolution test and evaluation of the correlation between in vivo and in vitro release
,”
Int. J. Pharm.
95
,
67
75
(
1993
).
21.
K.
Molly
,
M. V.
Woestyjne
, and
W.
Verstraete
, “
Development of a 5-step multi-chamber reactor as a simulation of the human intestinal microbial ecosystem
,”
Appl. Microbiol. Biotechnol.
39
,
254
258
(
1993
).
22.
J.
Yoo
and
X.
Chen
, “
GIT physiochemical modeling—A critical review
,”
Int. J. Food Eng.
2
,
1
7
(
2006
).
23.
F.
Kong
and
R.
Singh
, “
Disintegration of solid foods in human stomach
,”
J. Food Sci.
73
,
R67
R80
(
2008
).
24.
F.
Kong
and
R.
Singh
, “
A human gastric simulator (HGS) to study digestion in human stomach
,”
J. Food Sci.
75
,
E627
E635
(
2010
).
25.
M.
Wickham
,
R.
Faulks
, and
C.
Mills
, “
In vitro digestion methods for assessing the effect of food structure on allergen breakdown
,”
Mol. Nutr. Food Res.
53
,
952
958
(
2009
).
26.
D.
Dufour
,
F.
Tanner
,
K.
Feigl
,
Y.
Takeda
,
S.
Fischer
, and
E. J.
Windhab
, “
Study of the rheological properties of the retropulsive jet built by the antral contraction wave in a simplified artificial stomach
,” in
Proceedings of the 10th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering
,
Toyko, Japan
,
2016
.
27.
Y.
Takeda
, “
Velocity profile measurement by ultrasound Doppler shift method
,”
Int. J. Heat Fluid Flow
7
,
313
318
(
1986
).
28.
A.
Pal
,
K.
Indireshkumar
,
W.
Schwizer
,
B.
Abrahamsson
,
M.
Fried
, and
J.
Brasseur
, “
Gastric flow and mixing studied using computer simulation
,”
Proc. R. Soc. B
271
,
2587
2594
(
2004
).
29.
T.
Hausken
,
M.
Mundt
, and
M.
Samsom
, “
Low antroduodenal pressure gradients are responsible for gastric emptying of a low-caloric liquid meal in humans
,”
Neurogastroenterol. Motil.
14
,
97
105
(
2002
).
30.
A.
Pullan
,
L.
Cheng
,
R.
Yassi
, and
M.
Buist
, “
Modelling gastrointestinal bioelectric activity
,”
Prog. Biophys. Mol. Biol.
85
,
523
550
(
2004
).
31.
V.
Spitzer
,
M.
Ackerman
,
A.
Scherzinger
, and
D.
Whitlock
, “
The visible human male: A technical report
,”
J. Am. Med. Inf. Assoc.
3
,
118
130
(
1996
).
32.
C.
Skamniotis
,
M.
Elliott
, and
M.
Charalambides
, “
On modeling the large strain fracture behaviour of soft viscous foods
,”
Phys. Fluids
29
,
121610
(
2017
).
33.
M. J.
Ferrua
and
R. P.
Singh
, “
Modeling the fluid dynamics in a human stomach to gain insight of food digestion
,”
J. Food Sci.
75
,
151
162
(
2010
).
34.
M.
Ferrua
and
R.
Singh
, “
Understanding the fluid dynamics of gastric digestion using computational modeling
,”
Proc. Food Sci.
1
,
1465
1472
(
2011
).
35.
Anonymous, Fluent 6.3.26 documentation, Lebanon, NH; ANSYS, Inc., Canonsburg, PA, U.S.A.,
2007
.
36.
A.
Keet
, “
Infantile hypertrophic pyloric stenosis
,” in
The Pyloric Sphincteric Cylinder in Health and Disease
(
Springer
,
1993
), pp.
213
231
.
37.
OpenFOAM®
, The Openfoam Foundation, http://www.openfoam.org (
2017
).
38.
H.
Jasak
and
Z.
Tuković
, “
Automatic mesh motion for the unstructured finite volume method
,”
Trans. FAMENA
30
,
1
20
(
2006
).
39.
T.
Holzmann
,
Mathematics, Numerics
(
Derivations and OpenFOAM
,
2016
).
40.
O.
Keinke
,
M.
Schemann
, and
H.
Ehrlein
, “
Mechanical factors regulating gastric emptying of viscous nutrient meals in dogs
,”
Q. J. Exp. Physiol.
69
,
781
795
(
1984
).
41.
K.
Schulze-Delrieu
and
C.
Brown
, “
Emptying of saline meals by the cat stomach as a function of pyloric resistance
,”
Am. J. Physiol.: Gastrointest. Liver Physiol.
249
,
G725
G732
(
1985
).
42.
J. G.
Brasseur
,
S.
Corrsin
, and
N. Q.
Lu
, “
The influence of a peripheral layer of different viscosity on peristaltic pumping with Newtonian fluids
,”
J. Fluid Mech.
174
,
495
519
(
1987
).
43.
P.
Boulby
,
R.
Moore
,
P.
Gowland
, and
R.
Spiller
, “
Fat delays emptying but increases forward and backward antral flow as assessed by flow-sensitive magnetic resonance imaging
,”
Neurogastroenterol. Motil.
11
,
27
36
(
1999
).
44.
N.
Zuckerman
and
N.
Lior
, “
Radial slot jet impingement flow and heat transfer on a cylindrical target
,”
J. Thermophys. Heat Transfer
21
,
548
561
(
2007
).
45.
L.
Marciani
,
P.
Gowland
,
R.
Spiller
,
P.
Manoj
,
R.
Moore
,
P.
Young
, and
A.
Fillery-Travis
, “
Development of a 5-step multi-chamber reactor as a simulation of the human intestinal microbial ecosystem
,”
Am. J. Physiol.: Gastrointest. Liver Physiol.
280
,
G1227
G1233
(
2001
).
You do not currently have access to this content.