Experimental data are presented for large arrays of rotating, variable-height cylinders in order to study the dependence of the three-dimensional mean flows on the height heterogeneity of the array. Elements in the examined arrays were spatially arranged in the same staggered paired configuration, and the heights of each element pair varied up to ±37.5% from the mean height (kept constant across all arrays), such that the arrays were vertically structured. Four vertical structuring configurations were examined at a nominal Reynolds number (based on freestream velocity and cylinder diameter) of 600 and nominal tip-speed ratios of 0, 2, and 4. It was found that the vertical structuring of the array could significantly alter the mean flow patterns. Most notably, a net vertical flow into the array from above was observed, which was augmented by the arrays' vertical structuring, showing a 75% increase from the lowest to highest vertical flows (as evaluated at the maximum element height, at a single rotation rate). This vertical flow into the arrays is of particular interest as it represents an additional mechanism by which high streamwise momentum can be transported from above the array down into the array. An evaluation of the streamwise momentum resource within the array indicates up to a 56% increase in the incoming streamwise velocity to the elements (from the lowest to highest ranking arrays, at a single rotation rate). These arrays of rotating cylinders may provide insight into the flow kinematics of arrays of vertical axis wind turbines (VAWTs). In a physical VAWT array, an increase in incoming streamwise flow velocity to a turbine corresponds to a (cubic) increase in the power output of the turbine. Thus, these results suggest a promising approach to increasing the power output of a VAWT array.

References

References
1.
Chan
,
A. S.
,
Dewey
,
P. A.
,
Jameson
,
A.
,
Liang
,
C.
, and
Smits
,
A. J.
,
2011
, “
Vortex Suppression and Drag Reduction in the Wake of Counter-Rotating Cylinders
,”
J. Fluid Mech.
,
679
, pp.
343
382
.
2.
Guo
,
X.
,
Lin
,
J.
,
Tu
,
C.
, and
Wang
,
H.
,
2009
, “
Flow Past Two Rotating Circular Cylinders in a Side-by-Side Arrangement
,”
J. Hydrodyn.
,
21
(
2
), pp.
143
151
.
3.
Kumar
,
S.
,
Gonzalez
,
B.
, and
Probst
,
O.
,
2011
, “
Flow Past Two Rotating Cylinders
,”
Phys. Fluids
,
23
(
1
), p.
014102
.
4.
Ueda
,
Y.
,
Kida
,
T.
, and
Iguchi
,
M.
,
2013
, “
Steady Approach of Unsteady Low-Reynolds-Number Flow Past Two Rotating Circular Cylinders
,”
J. Fluid Mech.
,
736
, pp.
414
443
.
5.
Yoon
,
H. S.
,
Kim
,
J. H.
,
Chun
,
H. H.
, and
Choi
,
H. J.
,
2007
, “
Laminar Flow Past Two Rotating Circular Cylinders in a Side-by-Side Arrangement
,”
Phys. Fluids
,
19
(
12
), p.
128103
.
6.
Yoon
,
H. S.
,
Chun
,
H. H.
,
Kim
,
J. H.
, and
Park
,
I. L. R.
,
2009
, “
Flow Characteristics of Two Rotating Side-by-Side Circular Cylinder
,”
Comput. Fluids
,
38
(
2
), pp.
466
474
.
7.
Whittlesey
,
R. W.
,
Liska
,
S.
, and
Dabiri
,
J. O.
,
2010
, “
Fish Schools as a Basis for Vertical Axis Wind Turbine Farm Design
,”
Bioinspiration Biomimetics
,
5
(
3
), p.
035005
.
8.
Dabiri
,
J. O.
,
2011
, “
Potential Order-of-Magnitude Enhancement of Wind Farm Power Density Via Counter-Rotating Vertical-Axis Wind Turbine Arrays
,”
J. Renewable Sustainable Energy
,
3
(
4
), p.
043104
.
9.
Kinzel
,
M.
,
Mulligan
,
Q.
, and
Dabiri
,
J. O.
,
2012
, “
Energy Exchange in an Array of Vertical Axis Wind Turbines
,”
J. Turbul.
,
13
(
38
), pp.
1
13
.
10.
Craig
,
A.
,
Dabiri
,
J.
, and
Koseff
,
J.
,
2016
, “
A Kinematic Description of the Key Flow Characteristics in an Array of Finite-Height Rotating Cylinders
,”
ASME J. Fluids Eng.
,
138
(
7
), p.
070906
.
11.
Weitzman
,
J. S.
,
Zeller
,
R. B.
,
Thomas
,
F. I. M.
, and
Koseff
,
J. R.
,
2015
, “
The Attenuation of Current- and Wave-Driven Flow Within Submerged Multispecific Vegetative Canopies
,”
Limnol. Oceanogr.
,
60
(
6
), pp.
1855
1874
.
12.
Cheng
,
H.
, and
Castro
,
I. P.
,
2002
, “
Near Wall Flow Over Urban-Like Roughness
,”
Boundary-Layer Meteorolo.
,
104
(
2
), pp.
229
259
.
13.
Kanda
,
M.
,
2006
, “
Large-Eddy Simulation on the Effects of Surface Geometry of Building Arrays on Turbulent Organized Structures
,”
Boundary-Layer Meteorol.
,
118
(
1
), pp.
151
168
.
14.
Xie
,
Z. T.
,
Coceal
,
O.
, and
Castro
,
I. P.
,
2008
, “
Large-Eddy Simulation of Flows Over Random Urban-Like Obstacles
,”
Boundary-Layer Meteorol.
,
129
(
1
), pp.
1
23
.
15.
Jiang
,
D.
,
Jiang
,
W.
,
Liu
,
H.
, and
Sun
,
J.
,
2008
, “
Systematic Influence of Different Building Spacing, Height, and Layout on Mean Wind and Turbulent Characteristics Within and Over Urban Building Arrays
,”
Wind Struct.
,
11
(
4
), pp.
275
289
.
16.
Hagishima
,
A.
,
Tanimoto
,
J.
,
Nagayama
,
K.
, and
Meno
,
S.
,
2009
, “
Aerodynamic Parameters of Regular Arrays of Rectangular Blocks With Various Geometries
,”
Boundary-Layer Meteorol.
,
132
(
2
), pp.
315
337
.
17.
Millward-Hopkins
,
J. T.
,
Tomlin
,
A. S.
,
Ma
,
L.
,
Ingham
,
D.
, and
Pourkashanian
,
M.
,
2011
, “
Estimating Aerodynamic Parameters of Urban-Like Surfaces With Heterogeneous Building Heights
,”
Boundary-Layer Meteorol.
,
141
(
3
), pp.
443
465
.
18.
Ferreira
,
C. S.
,
Madsen
,
H. A.
,
Barone
,
M.
,
Roscher
,
B.
,
Deglaire
,
P.
, and
Arduin
,
I.
,
2014
, “
Comparison of Aerodynamic Models for Vertical Axis Wind Turbines
,”
J. Phys.: Conf. Ser.
,
524
, p.
012125
.
19.
Shamsoddin
,
S.
, and
Porte-Agel
,
F.
,
2014
, “
Large Eddy Simulation of Vertical Axis Wind Turbine Wakes
,”
Energies
,
7
(
2
), pp.
890
912
.
20.
Archer
,
C.
,
Xie
,
S.
,
Ghaisas
,
N.
, and
Meneveau
,
C.
,
2015
, “
Benefits of Vertically-Staggered Wind Turbines From Theoretical Analysis and Large-Eddy Simulations
,”
North American Wind Energy Academy Symposium
, Blacksburg, VA, June 9–11, pp.
3
6
.
21.
Nikora
,
V.
,
Ballio
,
F.
,
Coleman
,
S.
, and
Pokrajac
,
D.
,
2013
, “
Spatially Averaged Flows Over Mobile Beds: Definitions, Averaging Theorems, and Conservation Equations
,”
J. Hydraul. Eng.
,
139
(
8
), pp.
803
811
.
22.
Craig
,
A.
, and
Dabiri
,
J. O.
,
2015
, “
V-Shaped Arrangements of Turbines
,”
U.S. Patent No. 9,175,669 B2
.
23.
Efron
,
B.
, and
Tibshirani
,
R. J.
,
1993
,
An Introduction to the Bootstrap
(Monographs on Statistics and Applied Probability, Vol.
57
),
Chapman & Hall
,
New York
.
24.
Theunissan
,
R.
,
Sante
,
A. D.
,
Riethmuller
,
M. L.
, and
den Braembussche
,
R. A. V.
,
2008
, “
Confidence Estimation Using Dependent Circular Block Bootstrapping: Application to the Statistical Analysis of PIV Measurements
,”
Exp. Fluids
,
44
(
4
), pp.
591
596
.
25.
Patton
,
A.
,
2014
, “
matlab
Codes.”
26.
Cal
,
R. B.
,
Lebrón
,
J.
,
Castillo
,
L.
,
Kang
,
H. S.
, and
Meneveau
,
C.
,
2010
, “
Experimental Study of the Horizontally Averaged Flow Structure in a Model Wind-Turbine Array Boundary Layer
,”
J. Renewable Sustainable Energy
,
2
(
1
), p.
013106
.
27.
Calaf
,
M.
,
Meneveau
,
C.
, and
Meyers
,
J.
,
2010
, “
Large Eddy Simulation Study of Fully Developed Wind-Turbine Array Boundary Layers
,”
Phys. Fluids
,
22
(
1
), p.
015110
.
28.
Yue
,
W.
,
Meneveau
,
C.
,
Parlange
,
M.
,
Whu
,
W.
,
van Hout
,
R.
, and
Katz
,
J.
,
2007
, “
A Comparative Quadrant Analysis of Turbulence in a Plant Canopy
,”
Water Resources Research
,
43
(
5
), (epub May 17, 2007).
You do not currently have access to this content.