The connections between swimming technique and the fluid dynamical interactions they generate are important for assisting performance improvement. Computational fluid dynamics (CFD) modeling provides a controlled and unobtrusive way for understanding the fundamentals of swimming. A coupled biomechanical–smoothed particle hydrodynamics (SPH) fluid model is used to analyze the thrust and drag generation of a freestyle swimmer. The swimmer model was generated using a three-dimensional laser body scan of the athlete and digitization of multi-angle video footage. Two large distinct peaks in net streamwise thrust are found during the stroke, which coincide with the underwater arm strokes. The hand motions generate vortical structures that travel along the body toward the kicking legs and the hands are shown to produce thrust using both lift and drag. These findings advance understanding of the freestyle stroke and may be used to improve athlete technique.

References

References
1.
Wei
,
T.
,
Mark
,
R.
, and
Hutchison
,
S.
,
2014
, “
The Fluid Dynamics of Competitive Swimming
,”
Annu. Rev. Fluid Mech.
,
46
(
1
), pp.
547
565
.
2.
Bucher
,
W.
,
1975
, “
The Influence of the Leg Kick and the Arm Stroke on the Total Speed During the Crawl Stroke
,”
Swimming II: Second International Symposium on Biomechanics in Swimming
,
L.
Lewillie
, and
J. P.
Clarys
, eds.,
University Park Press
,
Baltimore, MD
, pp.
180
187
.
3.
Hollander
,
A. P.
,
De Groot
,
G.
,
van Ingen Schenau
,
G. J.
,
Kahman
,
R.
, and
Toussaint
,
H. M.
,
1988
, “
Contribution of the Legs to Propulsion in Front Crawl Swimming
,”
Swimming Science V
,
B.
Ungerechts
,
K.
Wilke
, and
K.
Reischle
, eds.,
Human Kinetics
,
Champaign, IL
, pp.
39
44
.
4.
Deschodt
,
V. J.
,
Arsac
,
L. M.
, and
Rouard
,
A. H.
,
1999
, “
Relative Contribution of Arms and Legs in Humans to Propulsion in 25-m Sprint Front-Crawl Swimming
,”
Eur. J. Appl. Physiol.
,
80
(
3
), pp.
192
199
.
5.
Counsilman
,
J. E.
,
1968
,
The Science of Swimming
,
Prentice-Hall
, Englewood Cliffs, NJ.
6.
Berger
,
M. A. M.
,
de Groot
,
G.
, and
Hollander
,
A. P.
,
1995
, “
Hydrodynamic Drag and Lift Forces on Human Hand/Arm Models
,”
J. Biomech.
,
28
(
2
), pp.
125
133
.
7.
Payton
,
C. J.
, and
Bartlett
,
R. M.
,
1995
, “
Estimating Propulsive Forces in Swimming From Three-Dimensional Kinematic Data
,”
J. Sports Sci.
,
13
(
6
), pp.
447
454
.
8.
Schleihauf
,
R. E.
,
1979
, “
A Hydrodynamic Analysis of Swimming Propulsion
,”
Swimming III
,
J.
Terauds
, and
E. W.
Bedingfield E.W.
, eds., University Park Press, Baltimore, MD, pp.
70
109
.
9.
Bixler
,
B.
, and
Riewald
,
S.
,
2002
, “
Analysis of a Swimmer's Hand and Arm in Steady Flow Conditions Using Computational Fluid Dynamics
,”
J. Biomech.
,
35
(
5
), pp.
713
717
.
10.
Minetti
,
A. E.
,
Machtsiras
,
G.
, and
Masters
,
J. C.
,
2009
, “
The Optimum Finger Spacing in Human Swimming
,”
J. Biomech.
,
42
(
13
), pp.
2188
2190
.
11.
Marinho
,
D. A.
,
Barbosa
,
T. M.
,
Reis
,
V. M.
,
Kjendlie
,
P. L.
,
Alves
,
F. B.
,
Vilas-Boas
,
J. P.
,
Machado
,
L.
,
Silva
,
A. J.
, and
Rouboa
,
A. I.
,
2010
, “
Swimming Propulsion Forces are Enhanced by a Small Finger Spread
,”
J. Appl. Biomech.
,
26
(
1
), pp.
87
92
.
12.
Marinho
,
D. A.
,
Silva
,
A. J.
,
Reis
,
V. M.
,
Barbosa
,
T. M.
,
Vilas-Boas
,
J. P.
,
Alves
,
F. B.
,
Machado
,
L.
, and
Rouboa
,
A. I.
,
2011
, “
Three-Dimensional CFD Analysis of the Hand and Forearm in Swimming
,”
J. Appl. Biomech.
,
27
(
1
), pp.
74
80
.
13.
Rouboa
,
A.
,
Silva
,
A.
,
Leal
,
L.
,
Rocha
,
J.
, and
Alves
,
F.
,
2006
, “
The Effect of Swimmer's Hand/Forearm Acceleration on Propulsive Forces Generation Using Computational Fluid Dynamics
,”
J. Biomech.
,
39
(
7
), pp.
1239
1248
.
14.
Von Loebbecke
,
A.
, and
Mittal
,
R.
,
2012
, “
Comparative Analysis of Thrust Production for Distinct Arm-Pull Styles in Competitive Swimming
,”
ASME J. Biomech. Eng.
,
134
(
7
), p.
074501
.
15.
Bixler
,
B.
,
Pease
,
D.
, and
Fairhurst
,
F.
,
2007
, “
The Accuracy of Computational Fluid Dynamics Analysis of the Passive Drag of a Male Swimmer
,”
Sports Biomech.
,
6
(
1
), pp.
81
98
.
16.
Zaïdi
,
H.
,
Fohanno
,
S.
,
Taïar
,
R.
, and
Polidori
,
G.
,
2010
, “
Turbulence Model Choice for the Calculation of Drag Forces When Using the CFD Method
,”
J. Biomech.
,
43
(
3
), pp.
405
411
.
17.
Marinho
,
D. A.
,
Reis
,
V. M.
,
Alves
,
F. B.
,
Vilas-Boas
,
J. P.
,
Machado
,
L.
,
Silva
,
A. J.
, and
Rouboa
,
A. I.
,
2009
, “
Hydrodynamic Drag During Gliding in Swimming
,”
J. Appl. Biomech.
,
25
(
3
), pp.
253
257
.
18.
Popa
,
C. V.
,
Arfaoui
,
A.
,
Fohanno
,
S.
,
Taïar
,
R.
, and
Polidori
,
G.
,
2014
, “
Influence of a Postural Change of the Swimmer's Head in Hydrodynamic Performances Using 3D CFD
,”
Comput. Methods Biomech. Biomed. Eng.
,
17
(
4
), pp.
344
351
.
19.
Lyttle
,
A.
, and
Keys
,
M.
,
2006
, “
The Application of Computational Fluid Dynamics for Technique Prescription in Underwater Kicking
,”
Port. J. Sport Sci.
,
6
(
2
), pp.
233
235
.
20.
Von Loebbecke
,
A.
,
Mittal
,
R.
,
Mark
,
R.
, and
Hahn
,
J.
,
2009
, “
A Computational Method for Analysis of Underwater Dolphin Kick Hydrodynamics in Human Swimming
,”
Sports Biomech.
,
8
(
1
), pp.
60
77
.
21.
Cohen
,
R. C. Z.
,
Cleary
,
P. W.
, and
Mason
,
B. R.
,
2012
, “
Simulations of Dolphin Kick Swimming Using Smoothed Particle Hydrodynamics
,”
Hum. Mov. Sci.
,
31
(
3
), pp.
604
619
.
22.
Keys
,
M.
,
Lyttle
,
A.
,
Blanksby
,
B. A.
, and
Cheng
,
L.
,
2010
, “
A Full Body Computational Fluid Dynamic Analysis of the Freestyle Stroke of a Previous Sprint Freestyle World Record Holder
,”
XIth International Symposium for Biomechanics and Medicine in Swimming
, Oslo, Norway, June 16–19, Paper No. O-075, pp.
105
107
.
23.
Cleary
,
P. W.
,
Cohen
,
R. C. Z.
,
Harrison
,
S. M.
,
Sinnott
,
M. D.
,
Prakash
,
M.
, and
Mead
,
S.
,
2013
, “
Prediction of Industrial, Biophysical and Extreme Geophysical Flows Using Particle Methods
,”
Eng. Comput.
,
30
(
2
), pp.
157
196
.
24.
Cohen
,
R. C. Z.
,
Cleary
,
P. W.
,
Harrison
,
S. M.
,
Mason
,
B. R.
, and
Pease
,
D. L.
,
2014
, “
Pitching Effects of Buoyancy During Four Competitive Swimming Strokes
,”
J. Appl. Biomech.
,
30
(
5
), pp.
609
618
.
25.
Monaghan
,
J. J.
,
1994
, “
Simulating Free Surface Flows With SPH
,”
J. Comput. Phys.
,
110
(
2
), pp.
399
406
.
26.
Cohen
,
R. C. Z.
, and
Cleary
,
P. W.
,
2010
, “
Computational Studies of the Locomotion of Dolphins and Sharks Using Smoothed Particle Hydrodynamics
,”
6th World Congress of Biomechanics
(
WCB 2010
), Singapore, Aug. 1–6, pp.
22
25
.
27.
Harrison
,
S. M.
,
Cohen
,
R. C. Z.
,
Cleary
,
P. W.
,
Mason
,
B. R.
, and
Pease
,
D. L.
,
2014
, “
Torque and Power About the Joints of the Arm During the Freestyle Stroke
,”
XII International Symposium on Biomechanics and Medicine in Swimming
, Canberra, Australia, Apr. 28–May 2, pp.
349
355
.
28.
Harrison
,
S. M.
,
Cohen
,
R. C. Z.
,
Cleary
,
P. W.
,
Barris
,
S.
, and
Rose
,
G.
, “
A Coupled Biomechanical–Smoothed Particle Hydrodynamics Model for Predicting The Loading on the Body During Elite Platform Diving
,”
Appl. Math. Model.
(submitted).
29.
Monaghan
,
J. J.
,
2005
, “
Smoothed Particle Hydrodynamics
,”
Rep. Prog. Phys.
,
68
(
8
), pp.
1703
1759
.
30.
Monaghan
,
J. J.
,
2012
, “
Smoothed Particle Hydrodynamics and Its Diverse Applications
,”
Annu. Rev. Fluid Mech.
,
44
(
1
), pp.
323
346
.
31.
Cleary
,
P. W.
,
Prakash
,
M.
,
Ha
,
J.
, and
Stokes
,
N.
,
2007
, “
Smooth Particle Hydrodynamics: Status and Future Potential
,”
Prog. Comput. Fluid Dyn.
,
7
(
2
), pp.
70
90
.
32.
Liu
,
M. B.
, and
Liu
,
G. R.
,
2010
, “
Smoothed Particle Hydrodynamics (SPH): An Overview and Recent Developments
,”
Arch. Comput. Methods Eng.
,
17
(
1
), pp.
25
76
.
33.
Cleary
,
P. W.
,
Ha
,
J.
,
Prakash
,
M.
, and
Nguyen
,
T.
,
2006
, “
3D SPH Flow Predictions and Validation for High Pressure Die Casting of Automotive Components
,”
Appl. Math. Model.
,
30
(
11
), pp.
1406
1427
.
34.
Prakash
,
M.
,
Cleary
,
P. W.
,
Ha
,
J.
,
Noui-Mehidi
,
M. N.
,
Blackburn
,
H.
, and
Brooks
,
G.
,
2007
, “
Simulation of Suspension of Solids in a Liquid in a Mixing Tank Using SPH and Comparison With Physical Modelling Experiments
,”
Prog. Comput. Fluid Dyn. Int. J.
,
7
(
2
), pp.
91
100
.
35.
Robinson
,
M.
,
Cleary
,
P.
, and
Monaghan
,
J.
,
2008
, “
Analysis of Mixing in a Twin Cam Mixer Using Smoothed Particle Hydrodynamics
,”
AIChE J.
,
54
(
8
), pp.
1987
1998
.
36.
Farahani
,
R. J.
, and
Dalrymple
,
R. A.
,
2014
, “
Three-Dimensional Reversed Horseshoe Vortex Structures Under Broken Solitary Waves
,”
Coast. Eng.
,
91
, pp.
261
279
.
37.
López
,
D.
,
Marivela
,
R.
, and
Garrote
,
L.
,
2010
, “
Smoothed Particle Hydrodynamics Model Applied to Hydraulic Structures: A Hydraulic Jump Test Case
,”
J. Hydraul. Res.
,
48
(
S1
), pp.
142
158
.
38.
Shao
,
S.
,
2009
, “
Incompressible SPH Simulation of Water Entry of a Free-Falling Object
,”
Int. J. Numer. Methods Fluids
,
59
(
1
), pp.
91
115
.
39.
Hieber
,
S. E.
, and
Koumoutsakos
,
P.
,
2008
, “
An Immersed Boundary Method for Smoothed Particle Hydrodynamics of Self-Propelled Swimmers
,”
J. Comput. Phys.
,
227
(
19
), pp.
8636
8654
.
40.
Cummins
,
S. J.
,
Silvester
,
T. B.
, and
Cleary
,
P. W.
,
2012
, “
Three-Dimensional Wave Impact on a Rigid Structure Using Smoothed Particle Hydrodynamics
,”
Int. J. Numer. Methods Fluids
,
68
(
12
), pp.
1471
1496
.
41.
Monaghan
,
J. J.
,
1995
, “
Simulating Gravity Currents With SPH: III Boundary Forces
,” Department of Mathematics, Monash University, Victoria, Australia, Report No. 95/11.
42.
Rudman
,
M.
,
Cleary
,
P. W.
, and
Prakash
,
M.
,
2009
, “
Simulation of Liquid Sloshing in a Model LNG Tank Using Smoothed Particle Hydrodynamics
,”
Int. J. Offshore Polar Eng.
,
19
(4), pp.
286
294
.
43.
Jeong
,
J.
, and
Hussain
,
F.
,
1995
, “
On the Identification of a Vortex
,”
J. Fluid Mech.
,
285
, pp.
69
94
.
44.
Toussaint
,
H. M.
,
Truijens
,
M.
,
Elzinga
,
M. J.
,
Van de Ven
,
A.
,
de Best
,
H.
,
Snabel
,
B.
, and
de Groot
,
G.
,
2002
, “
Effect of a Fast-Skin™ ‘Body’ Suit on Drag During Front Crawl Swimming
,”
Sports Biomech.
,
1
(
1
), pp.
1
10
.
45.
Arellano
,
R.
,
Brown
,
P.
,
Cappaert
,
J.
, and
Nelson
,
R. C.
,
1994
, “
Analysis of 50-, 100-, and 200-m Freestyle Swimmers at the 1992 Olympic Games
,”
J. Appl. Biomech.
,
10
, pp.
189
199
.
46.
Hochstein
,
S.
, and
Blickhan
,
R.
,
2011
, “
Vortex Re-Capturing and Kinematics in Human Underwater Undulatory Swimming
,”
Hum. Mov. Sci.
,
30
(
5
), pp.
998
1007
.
47.
Pacholak
,
S.
,
Hochstein
,
S.
,
Rudert
,
A.
, and
Brücker
,
C.
,
2014
, “
Unsteady Flow Phenomena in Human Undulatory Swimming: A Numerical Approach
,”
Sports Biomech.
,
13
(
2
), pp.
176
194
.
48.
Vennell
,
R.
,
Pease
,
D.
, and
Wilson
,
B.
,
2006
, “
Wave Drag on Human Swimmers
,”
J. Biomech.
,
39
(
4
), pp.
664
671
.
49.
Marinho
,
D. A.
,
Rouboa
,
A. I.
,
Alves
,
F. B.
,
Vilas-Boas
,
J. P.
,
Machado
,
L.
,
Reis
,
V. M.
, and
Silva
,
A. J.
,
2009
, “
Hydrodynamic Analysis of Different Thumb Positions in Swimming
,”
J. Sports Sci. Med.
,
8
(
1
), pp.
58
66
.
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