Numerical and experimental studies of energy harvesting driven by vortex-induced vibration (VIV) are currently focused on arranging the energy-captured structure in a uniform incoming flow at a certain depth, ignoring the effect of the free surface on VIV. The fluid–structure coupling effect can be enhanced when a column-group structure with rigid connection is arranged under uniform flow, which is helpful for the structure to concentrate hydrokinetic energy from low-velocity water flow. In this paper, a staggered arrangement of a four-cylinder oscillator with rigid connections is proposed as the energy converter, and the fluid–solid interaction numerical method is carried out to simulate the VIV of the four-cylinder structure under single-phase flow and free surfaces. In U* = 2–16 (flow velocity U = 0.16–1.28 m/s), the results of the energy harvesting magnitude, efficiency, and density of the four-cylinder oscillator under the arrangement depth ratios S* = 2, S* = 3, S* = 4, and S* = 5 are compared with the results obtained in the single-phase flow. It was found that the column-group structure has a broader resonance range of VIV in single-phase flows than a single cylinder and can capture more hydrokinetic energy concentratedly from low-velocity flow. The VIV responses of the four-cylinder oscillator are suppressed at low submergence depths with a narrower resonance range, and its captured energy is reduced. In contrast, at high submergence depth ratio S*, the VIV responses are not suppressed obviously by the free surface. The magnitude of captured energy, energy-harvesting efficiency, and density of the four-cylinder structure are basically consistent with the results obtained in single-phase flow at S* = 5.

1.
S.
Zhang
,
X.
Bai
,
C.
Zhao
 et al., “
China's carbon budget inventory from 1997 to 2017 and its challenges to achieving carbon neutral strategies
,”
J. Cleaner Prod.
347
,
130966
(
2022
).
2.
E. S.
Kim
,
H.
Sun
,
H.
Park
 et al., “
Development of an alternating lift converter utilizing flow-induced oscillations to harness horizontal hydrokinetic energy
,”
Renewable Sustainable Energy Rev.
145
(
4
),
111094
(
2021
).
3.
N. D.
Laws
and
B. P.
Epps
, “
Hydrokinetic energy conversion: Technology, research, and outlook
,”
Renewable Sustainable Energy Rev.
57
,
1245
1259
(
2016
).
4.
J.
Wang
,
L.
Geng
,
L.
Ding
 et al., “
The state-of-the-art review on energy harvesting from flow-induced vibrations
,”
Appl. Energy
267
,
114902
(
2020
).
5.
M. M.
Bernitsas
,
K.
Raghavan
,
Y.
Ben-Simon
 et al., “
VIVACE (vortex induced vibration aquatic clean energy): A new concept in generation of clean and renewable energy from fluid flow
,”
J. Offshore Mech. Arct. Eng.
130
(
4
),
041101
(
2008
).
6.
M. M.
Bernitsas
,
Y.
Ben-Simon
,
K.
Raghavan
 et al., “
The VIVACE converter: Model tests at high damping and Reynolds number around 105
,” in
Proceedings of 25th International Conference on Offshore Mechanics and Arctic Engineering
(
ASME
,
2006
), Vol.
2
, pp.
639
653
.
7.
T.
Sarpkaya
, “
Discussion: On the paper by A. Khalak & C. H. K. Williamson. ‘Dynamics of a hydroelastic cylinder with very low mass and damping,’ JFS 1996, 10, 455–472
,”
J. Fluids Struct.
11
(
5
),
549
552
(
1997
).
8.
K.
Raghavan
and
M. M.
Bernitsas
, “
Experimental investigation of Reynolds number effect on vortex induced vibration of rigid circular cylinder on elastic supports
,”
Ocean Eng.
38
(
5–6
),
719
731
(
2011
).
9.
M. M.
Zdravkovich
 et al., “
Flow around circular cylinders—Volume 1: Fundamentals
,”
J. Fluids Eng.
120
(
1
),
105
106
(
1998
).
10.
J. H.
Lee
,
N.
Xiros
, and
M. M.
Bernitsas
, “
Virtual damper–spring system for VIV experiments and hydrokinetic energy conversion
,”
Ocean Eng.
38
(
5–6
),
732
747
(
2011
).
11.
C.-C.
Chang
,
R.
Ajith Kumar
, and
M. M.
Bernitsas
, “
VIV and galloping of single circular cylinder with surface roughness at 3.0 × 104 ≤ Re ≤ 1.2 × 105
,”
Ocean Eng.
38
(
16
),
1713
1732
(
2011
).
12.
N.
Li
,
H.
Park
,
H.
Sun
 et al., “
Hydrokinetic energy conversion using flow induced oscillations of single-cylinder with large passive turbulence control
,”
Appl. Energy
308
,
118380
(
2022
).
13.
L.
Ding
,
L.
Zhang
,
M. M.
Bernitsas
 et al., “
Numerical simulation and experimental validation for energy harvesting of single-cylinder VIVACE converter with passive turbulence control
,”
Renewable Energy
85
,
1246
1259
(
2016
).
14.
H.
Park
,
R.
Ajith Kumar
, and
M. M.
Bernitsas
, “
Suppression of vortex-induced vibrations of rigid circular cylinder on springs by localized surface roughness at 3 × 104 ≤ Re ≤ 1.2 × 105
,”
Ocean Eng.
111
,
218
233
(
2016
).
15.
H.
Park
,
R. A.
Kumar
, and
M. M.
Bernitsas
, “
Enhancement of flow-induced motion of rigid circular cylinder on springs by localized surface roughness at 3 × 104 ≤ Re ≤ 1.2 × 105
,”
Ocean Eng.
72
,
403
415
(
2013
).
16.
H.
Sun
and
M. M.
Bernitsas
, “
Bio-inspired adaptive damping in hydrokinetic energy harnessing using flow-induced oscillations
,”
Energy
176
,
940
960
(
2019
).
17.
H.
Sun
,
M. M.
Bernitsas
, and
M.
Turkol
, “
Adaptive harnessing damping in hydrokinetic energy conversion by two rough tandem-cylinders using flow-induced vibrations
,”
Renewable Energy
149
,
828
860
(
2020
).
18.
H.
Sun
,
C.
Ma
, and
M. M.
Bernitsas
, “
Hydrokinetic power conversion using flow induced vibrations with cubic restoring force
,”
Energy
153
,
490
508
(
2018
).
19.
J. H.
Lee
and
M. M.
Bernitsas
, “
High-damping, high-Reynolds VIV tests for energy harnessing using the VIVACE converter
,”
Ocean Eng.
38
(
16
),
1697
1712
(
2011
).
20.
E. S.
Kim
,
M. M.
Bernitsas
, and
R. A.
Kumar
, “
Multi-cylinder flow-induced motions: Enhancement by passive turbulence control at 28,000 < Re < 120,000
,”
J. Offshore Mech. Arct. Eng.
135
(
2
),
249
260
(
2011
).
21.
E. S.
Kim
and
M. M.
Bernitsas
, “
Performance prediction of horizontal hydrokinetic energy converter using multiple-cylinder synergy in flow induced motion
,”
Appl. Energy
170
,
92
100
(
2016
).
22.
B.
Zhang
,
Z.
Mao
,
B.
Song
 et al., “
Numerical investigation on VIV energy harvesting of four cylinders in close staggered formation
,”
Ocean Eng.
165
,
55
68
(
2018
).
23.
B.
Zhang
,
Z.
Mao
,
L.
Wang
 et al., “
A novel V-shaped layout method for VIV hydrokinetic energy converters inspired by geese flying in a V-formation
,”
Energy
230
,
120811
(
2021
).
24.
P.
Han
,
G.
Pan
,
B.
Zhang
 et al., “
Three-cylinder oscillator under flow: Flow induced vibration and energy harvesting
,”
Ocean Eng.
21
,
107619
(
2020
).
25.
M.
Gu
,
B.
Song
,
B.
Zhang
 et al., “
The effects of submergence depth on vortex-induced vibration (VIV) and energy harvesting of a circular cylinder
,”
Renewable Energy
151
,
931
945
(
2020
).
26.
B.
Zhang
,
B.
Song
,
B.
Li
 et al., “
Numerical study of the effect of submergence depth on hydrokinetic energy conversion of an elastically mounted square cylinder in FIV
,”
Ocean Eng.
200
,
107030
(
2020
).
27.
W.
Xu
,
M.
Yang
,
E.
Wang
 et al., “
Performance of single-cylinder VIVACE converter for hydrokinetic energy harvesting from flow-induced vibration near a free surface
,”
Ocean Eng.
218
,
108168
(
2020
).
28.
B.
Zhang
,
B.
Li
,
S.
Fu
 et al., “
Experimental investigation of the effect of high damping on the VIV energy converter near the free surface
,”
Energy
244
,
122677
(
2022
).
29.
L.
Zhumei
,
N.
Cong
, and
G.
Tao
, “
Study on centralized harvesting ocean current energy with column-group structure by VIV
,”
Acta Energ. Sol. Sin.
42
(
04
),
89
94
(
2021
).
30.
O.
Reynolds
, “
On the dynamical theory of incompressible viscous fluids and the determination of the criterion
,”
Philos. Trans. R. Soc.-Math. Phys. Sci.
186
,
123
164
(
1895
).
31.
J.
Wang
,
W.
Zhao
,
Z.
Su
 et al., “
Enhancing vortex-induced vibrations of a cylinder with rod attachments for hydrokinetic power generation
,”
Mech. Syst. Signal Process.
145
,
106912
(
2020
).
32.
A.
Khalak
and
C.
Williamson
, “
Dynamics of a hydroelastic cylinder with very low mass and damping
,”
J. Fluids Struct.
10
(
5
),
455
472
(
1996
).
You do not currently have access to this content.