Under normal healthy conditions, blood flow in the carotid artery bifurcation is laminar. However, in the presence of a stenosis, the flow can become turbulent at the higher Reynolds numbers during systole. There is growing consensus that the transitional $k−ω$ model is the best suited Reynolds averaged turbulence model for such flows. Further confirmation of this opinion is presented here by a comparison with the RNG $k−ϵ$ model for the flow through a straight, nonbifurcating tube. Unlike similar validation studies elsewhere, no assumptions are made about the inlet profile since the full length of the experimental tube is simulated. Additionally, variations in the inflow turbulence quantities are shown to have no noticeable affect on downstream turbulence intensity, turbulent viscosity, or velocity in the $k−ϵ$ model, whereas the velocity profiles in the transitional $k−ω$ model show some differences due to large variations in the downstream turbulence quantities. Following this validation study, the transitional $k−ω$ model is applied in a three-dimensional parametrically defined computer model of the carotid artery bifurcation in which the sinus bulb is manipulated to produce mild, moderate, and severe stenosis. The parametric geometry definition facilitates a powerful means for investigating the effect of local shape variation while keeping the global shape fixed. While turbulence levels are generally low in all cases considered, the mild stenosis model produces higher levels of turbulent viscosity and this is linked to relatively high values of turbulent kinetic energy and low values of the specific dissipation rate. The severe stenosis model displays stronger recirculation in the flow field with higher values of vorticity, helicity, and negative wall shear stress. The mild and moderate stenosis configurations produce similar lower levels of vorticity and helicity.

1.
Beaglehole
,
R.
,
Irwin
,
A.
, and
Prentice
,
T.
, 2003, “
Facts and Figures: The World Health Report 2003—Shaping the Future
,” World Health Organization, Tech. Rep.
2.
Ku
,
D.
, 1997, “
Blood Flow in Arteries
,”
Annu. Rev. Fluid Mech.
0066-4189,
29
, pp.
399
434
.
3.
Berger
,
S.
, and
Jou
,
L.
, 2000, “
Flows in Stenotic Vessels
,”
Annu. Rev. Fluid Mech.
0066-4189,
32
, pp.
347
382
.
4.
Schulz
,
U. G.
, and
Rothwell
,
P. M.
, 2001, “
Major Variation in Carotid Artery Bifurcation Anatomy —A Possible Risk Factor for Plaque Development?
,”
Stroke
0039-2499,
32
, pp.
2522
2529
.
5.
Ghalichi
,
F.
,
Deng
,
X.
,
De Champlain
,
A.
,
Douville
,
Y.
,
King
,
M.
, and
Guidoin
,
R.
, 1998, “
Low Reynolds Number Turbulence Modeling of Blood Flow in Arterial Stenoses
,”
Biorheology
0006-355X,
35
, pp.
281
294
.
6.
Stroud
,
J.
,
Berger
,
S.
, and
Saloner
,
D.
, 2002, “
Numerical Analysis of Flow Through a Severely Stenotic Carotid Artery Bifurcation
,”
ASME J. Biomech. Eng.
0148-0731,
124
, pp.
9
20
.
7.
Ryval
,
J.
,
Straatman
,
A.
, and
Steinman
,
D.
, 2004, “
Two-Equation Turbulence Modeling of Pulsatile Flow in a Stenosed Tube
,”
ASME J. Biomech. Eng.
0148-0731,
126
, pp.
625
635
.
8.
Younis
,
B.
, and
Berger
,
S.
, 2004, “
A Turbulence Model for Pulsatile Arterial Flows
,”
ASME J. Biomech. Eng.
0148-0731,
126
, pp.
578
584
.
9.
Mittal
,
R.
,
Simmons
,
S.
, and
Udaykumar
,
H.
, 2001, “
Application of Large-Eddy Simulation to the Study of Pulsatile Flow in a Modeled Arterial Stenosis
,”
ASME J. Biomech. Eng.
0148-0731,
123
, pp.
325
332
.
10.
Mittal
,
R.
,
Simmons
,
S.
, and
Najjar
,
F.
, 2003, “
Numerical Study of Pulsatile Flow in a Constricted Channel
,”
J. Fluid Mech.
0022-1120,
485
, pp.
337
378
.
11.
Ahmed
,
S.
, and
Giddens
,
D.
, 1984, “
Pulsatile Poststenotic Flow Studies with Laser Doppler Anemometry
,”
J. Biomech.
0021-9290,
17
, pp.
695
705
.
12.
Varghese
,
S.
, and
Frankel
,
S.
, 2003, “
Numerical Modeling of Pulsatile Turbulent Flow in a Stenosed Tube
,”
ASME J. Biomech. Eng.
0148-0731,
126
, pp.
625
635
.
13.
Fluent Inc.
, 2003, The Fluent 6.1 Users Manual, Lebanon, NH.
14.
Smith
,
R.
,
Rutt
,
B.
,
Fox
,
A.
, and
Rankin
,
R.
, 1996, “
Geometric Characterization of Stenosed Human Carotid Arteries
,”
Radiology
0033-8419,
3
, pp.
898
911
.
15.
Ding
,
Z.
,
Wang
,
K.
,
Li
,
J.
, and
Cong
,
X.
, 2001, “
Flow Field and Oscillatory Shear Stress in a Tuning-Fork-Shaped Model of the Average Human Carotid Bifurcation
,”
J. Biomech.
0021-9290,
34
, pp.
1555
1562
.
16.
Bharadvaj
,
B.
,
Mabon
,
R.
, and
Giddens
,
D.
, 1982, “
Steady Flow in a Model of a Human Carotid Bifurcation. Part 1—Flow Visualization
,”
J. Biomech.
0021-9290,
15
, pp.
349
362
.
17.
Bressloff
,
N.
,
Forrester
,
A.
,
Banks
,
J.
, and
Kolachalama
,
V.
, 2004, “
Shape Optimization of the Carotid Artery Bifurcation
,”
Proceedings 5th ASMO UK∕ISSMO Conference on Engineering Design Optimisation
, Stratford-upon-Avon, UK, July 12–13.
18.
Holdsworth
,
D.
,
Norley
,
C.
,
Frayne
,
R.
,
Steinman
,
D.
, and
Rutt
,
B.
, 1999, “
Characterization of Common Carotid Artery Blood-Flow Waveforms in Normal Human Subjects
,”
Physiol. Meas
0967-3334,
20
, pp.
219
240
.
19.
Poepping
,
T. L.
,
Nikolov
,
H. N.
,
Rankin
,
R. N.
,
Lee
,
M.
, and
Holdsworth
,
D. W.
, 2002, “
An in Vitro System for Doppler Ultrasound Flow Studies in the Stenosed Carotid Artery Bifurcation
,”
Ultrasound Med. Biol.
0301-5629,
28
(
4
), pp.
495
506
.
20.
Steinman
,
D.
,
Poepping
,
T.
,
Tambasco
,
M.
,
Rankin
,
R.
, and
Holdsworth
,
D.
, 2000, “
Flow Patterns at the Stenosed Carotid Bifurcation: Effect of Concentric Versus Eccentric Stenosis
,”
Ann. Biomed. Eng.
0090-6964,
28
, pp.
415
423
.
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