The flow around a surface-mounted finite-height square prism was investigated using a low-speed wind tunnel. The experiments were conducted at a Reynolds number of Re = 7.3 × 104 for prism aspect ratios of AR = 3, 5, 7, 9, and 11 and incidence angles from α = 0 deg to 45 deg. The thickness of the boundary layer on the ground plane relative to the side length was δ/D = 1.5. Measurements of the vortex shedding frequency were made with a single-component hot-wire probe, and measurements of the mean drag and lift forces were obtained with a force balance. For all aspect ratios and incidence angles, the mean drag coefficient and Strouhal number were lower than those of an infinite prism, while the mean lift coefficient was of nearly similar magnitude. As the aspect ratio was increased from AR = 3 to 11, the force coefficients and Strouhal number slowly approached the infinite-square-prism data. The mean drag coefficient and Strouhal number for the finite prism were less sensitive to changes in incidence angle compared to the infinite square prism. The critical incidence angle, corresponding to minimum mean drag coefficient, minimum (most negative) mean lift coefficient, and maximum Strouhal number, shifted to a higher incidence angle compared to the infinite square prism, with values ranging from αcritical = 15 deg to 18 deg; this shift was greatest for the prisms of higher aspect ratio. The behavior of the force coefficients and Strouhal number for the prism of AR = 3 was distinct from the other prisms (with lower values of mean drag coefficient and mean lift coefficient magnitude, and a different Strouhal number trend), suggesting the critical aspect ratio was between AR = 5 and AR = 3 in these experiments. In the wall-normal direction, the power spectra for AR = 11 and 9 tended to have weaker and/or more broad-banded vortex shedding peaks near the ground plane and near the free end at α = 0 deg and 15 deg. For AR = 7 to 3, well-defined vortex shedding peaks were detected along the entire height of the prisms. For AR = 11 and 9, at α = 30 deg and 45 deg, vortex shedding peaks were absent in the power spectra in the upper part of the wake.

References

References
1.
Bearman
,
P. W.
, and
Trueman
,
D. M.
,
1972
, “
An Investigation of the Flow Around Rectangular Cylinders
,”
Aeronaut. Quart.
,
23
, pp.
229
237
.
2.
Lee
,
B. E.
,
1975
, “
The Effect of Turbulence on the Surface Pressure Field of a Square Prism
,”
J. Fluid Mech.
,
69
, pp.
263
282
.10.1017/S0022112075001437
3.
Rockwell
,
D. O.
,
1977
, “
Organized Fluctuations Due to Flow Past a Square Cross Section Cylinder
,”
ASME J. Fluids Eng.
,
99
, pp.
511
516
.10.1115/1.3448831
4.
Obasaju
,
E. D.
,
1983
, “
An Investigation of the Effects of Incidence on the Flow Around a Square Section Cylinder
,”
Aeronaut. Quart.
,
34
, pp.
243
259
.
5.
Igarashi
,
T.
,
1984
, “
Characteristics of the Flow Around a Square Prism
,”
Bull. JSME
,
27
, pp.
1858
1865
.10.1299/jsme1958.27.1858
6.
Knisely
,
C. W.
,
1990
, “
Strouhal Numbers of Rectangular Cylinders at Incidence: A Review and New Data
,”
J. Fluids Struct.
,
4
, pp.
371
393
.10.1016/0889-9746(90)90137-T
7.
Norberg
,
C.
,
1993
, “
Flow Around Rectangular Cylinders: Pressure Forces and Wake Frequencies
,”
J. Wind Eng. Indust. Aerodyn.
,
49
, pp.
187
196
.10.1016/0167-6105(93)90014-F
8.
Lyn
,
D. A.
,
Einav
,
S.
,
Rodi
,
W.
, and
Park
,
J. H.
,
1995
, “
A Laser-Doppler Velocimetry Study of Ensemble-Averaged Characteristics of the Turbulent Near Wake of a Square Cylinder
,”
J. Fluid Mech.
,
304
, pp.
285
319
.10.1017/S0022112095004435
9.
Dutta
,
S.
,
Muralidhar
,
K.
, and
Panigrahi
,
P. K.
,
2003
, “
Influence of the Orientation of a Square Cylinder on the Wake Properties
,”
Exp. Fluids
34
,
16
23
.10.1007/s00348-002-0484-x
10.
Yen
,
S. C.
, and
Yang
,
C. W.
,
2011
, “
Flow Patterns and Vortex Shedding Behavior Behind a Square Cylinder
,”
J. Wind Eng. Indust. Aerodyn.
,
99
, pp.
868
878
.10.1016/j.jweia.2011.06.006
11.
Yen
,
S. C.
, and
Yang
,
C. W.
,
2012
. “
Characteristic Flow Field Behind a Square-Cylinder Using Upstream Mesh Fences
,”
ASME J. Fluids Eng.
,
134
, p.
091202
.10.1115/1.4004904
12.
Sakamoto
,
H.
, and
Arie
,
M.
,
1983
, “
Vortex Shedding from a Rectangular Prism and a Circular Cylinder Placed Vertically in a Turbulent Boundary Layer
,”
J. Fluid Mech.
,
126
, pp.
147
165
.10.1017/S0022112083000087
13.
Sumner
,
D.
,
Heseltine
,
J. L.
, and
Dansereau
,
O. J. P.
,
2004
, “
Wake Structure of a Finite Circular Cylinder of Small Aspect Ratio
,”
Exp. Fluids
,
37
, pp.
720
730
.10.1007/s00348-004-0862-7
14.
Adaramola
,
M. S.
,
Akinlade
,
O. J.
,
Sumner
,
D.
,
Bergstrom
,
D. J.
, and
Schenstead
,
A. J.
,
2006
, “
Turbulent Wake of a Finite Circular Cylinder of Small Aspect Ratio
,”
J. Fluids Struct.
,
22
, pp.
919
928
.10.1016/j.jfluidstructs.2006.04.007
15.
Sohankar
,
A.
,
Norberg
,
C.
, and
Davidson
,
L.
,
1997
, “
Numerical Simulation of Unsteady Low-Reynolds Number Flow Around Rectangular Cylinders at Incidence
,”
J. Wind Eng. Indust. Aerodyn.
,
69–71
, pp.
189
201
.10.1016/S0167-6105(97)00154-2
16.
Obasaju
,
E. D.
,
1979
, “
On the Effects of End Plates on the Mean Forces on Square Sectioned Cylinders
,”
J. Indust. Aerodyn.
,
5
, pp.
179
186
.10.1016/0167-6105(79)90030-8
17.
Okajima
,
A.
,
1982
, “
Strouhal Numbers of Rectangular Cylinders
,”
J. Fluid Mech.
,
123
, pp.
379
398
.10.1017/S0022112082003115
18.
Huang
,
R. F.
,
Lin
,
B. H.
, and
Yen
,
S. C.
,
2010
, “
Time-Averaged Topological Flow Patterns and their Influence on Vortex Shedding of a Square Cylinder in Crossflow at Incidence
,”
J. Fluids Struct.
,
26
, pp.
406
429
.10.1016/j.jfluidstructs.2010.01.003
19.
Chen
,
J. M.
, and
Liu
,
C. H.
,
1999
, “
Vortex Shedding and Surface Pressures on a Square Cylinder at Incidence to a Uniform Air Stream
,”
Int. J. Heat Fluid Flow
,
20
, pp.
592
597
.10.1016/S0142-727X(99)00047-8
20.
Okamoto
,
S.
,
Tsunoda
,
K.
,
Takagi
,
T.
,
Okada
,
E.
, and
Kitani
,
K.
,
1995
, “
Turbulent Near Wake Behind Square Cylinder of Finite Length on Ground Plane
,”
ASME/JSME Fluids Engineering and Laser Anemometry Conference and Exhibition
, Hilton Head, SC, August 13–18, pp.
195
216
.
21.
Sakamoto
,
H.
,
Moriya
,
M.
,
Taniguchi
,
S.
, and
Arie
,
M.
,
1982
, “
The Form Drag of Three-Dimensional Bluff Bodies Immersed in Turbulent Boundary Layers
,”
ASME J. Fluids Eng.
,
104
, pp.
326
334
.10.1115/1.3241841
22.
Martinuzzi
,
R.
, and
Tropea
,
C.
,
1993
, “
The Flow Around Surface-Mounted, Prismatic Obstacles Placed in a Fully Developed Channel Flow
,”
ASME J. Fluids Eng.
,
115
, pp.
85
92
.10.1115/1.2910118
23.
Sarode
,
R. S.
,
Gai
,
S. L.
, and
Ramesh
,
C. K.
,
1981
, “
Flow Around Circular- and Square-Section Models of Finite Height in a Turbulent Shear Flow
,”
J. Wind Eng. Indust. Aerodyn.
,
8
, pp.
223
230
.10.1016/0167-6105(81)90022-2
24.
Sakamoto
,
H.
, and
Oiwake
,
S.
,
1984
, “
Fluctuating Forces on a Rectangular Prism and a Circular Cylinder Placed Vertically in a Turbulent Boundary Layer
,”
ASME J. Fluids Eng.
,
106
, pp.
160
166
.10.1115/1.3243093
25.
Sakamoto
,
H.
,
1985
, “
Aerodynamic Forces Acting on a Rectangular Prism Placed Vertically in a Turbulent Boundary Layer
,”
J. Wind Eng. Indust. Aerodyn.
,
18
, pp.
131
151
.10.1016/0167-6105(85)90093-5
26.
Sattari
,
P.
,
Bourgeois
,
J. A.
, and
Martinuzzi
,
R. J.
,
2010
, “
Turbulent Wake of Surface-Mounted Finite Aspect Ratio Bluff Bodies: Effect of Aspect Ratio and Cross Section Shape
,”
ASME 2010 3rd Joint US-European Fluids Engineering Division Summer Meeting, Montréal, Canada, Aug. 1–5
,
ASME
Paper No. FEDSM-ICNMM2010-30811. 10.1115/FEDSM-ICNMM2010-30811
27.
Wang
,
H. F.
,
Zhou
,
Y.
,
Chan
,
C.
, and
Lam
,
K. S.
,
2006
, “
Effect of Initial Conditions on Interaction Between a Boundary Layer and a Wall-Mounted Finite-Length Cylinder Wake
,”
Phys. Fluids
,
18
, p.
065106
.10.1063/1.2212329
28.
Wang
,
H. F.
, and
Zhou
,
Y.
,
2009
, “
The Finite-Length Square Cylinder Near Wake
,”
J. Fluid Mech.
,
638
, pp.
453
490
.10.1017/S0022112009990693
29.
Bourgeois
,
J. A.
,
Sattari
,
P.
, and
Martinuzzi
,
R. J.
,
2011
, “
Alternating Half-Loop Shedding in the Turbulent Wake of a Finite Surface-Mounted Square Cylinder With a Thin Boundary Layer
,”
Phys. Fluids
,
23
, p.
095101
.10.1063/1.3623463
30.
Sattari
,
P.
,
Bourgeois
,
J. A.
, and
Martinuzzi
,
R. J.
,
2012
, “
On the Vortex Dynamics in the Wake of a Finite Surface-Mounted Square Cylinder
,”
Exp. Fluids
,
52
, pp.
1149
1167
.10.1007/s00348-011-1244-6
31.
Kawai
,
H.
,
Okuda
,
Y.
, and
Ohashi
,
M.
,
2012
, “
Near Wake Structure Behind a 3D Square Prism With the Aspect Ratio of 2.7 in a Shallow Boundary Layer Flow
,”
J. Wind Eng. Indust. Aerodyn.
,
104–106
, pp.
196
202
.10.1016/j.jweia.2012.04.019
32.
Lee
,
H. H.
, and
Miau
,
J. J.
,
2012
, “
An Investigation on Karman-Type Vortex Shedding From a Finite Square Cylinder
,”
J. Mech.
,
28
(
2
), pp.
299
308
.10.1017/jmech.2012.33
33.
Rostamy
,
N.
,
McClean
,
J. F.
,
Sumner
,
D.
,
Bergstrom
,
D. J.
, and
Bugg
,
J. D.
,
2012
, “
Local Flow Field of a Surface–Mounted Finite Square Prism
,”
7th International Colloquium on Bluff Body Aerodynamics and Applications (BBAA7)
,
Shanghai, China
, Sept. 2–6.
34.
Sau
,
A.
,
Hwang
,
R. R.
,
Sheu
,
T. W. H.
, and
Yang
,
W. C.
,
2003
, “
Interaction of Trailing Vortices in the Wake of a Wall-Mounted Rectangular Cylinder
,”
Phys. Rev. E
,
68
, p.
056303
.10.1103/PhysRevE.68.056303
35.
Einian
,
M.
,
Bergstrom
,
D. J.
, and
Sumner
,
D.
,
2009
, “
Large Eddy Simulation of Flow Over a Finite Square Cylinder
,”
6th International Symposium on Turbulence, Heat and Mass Transfer (THMT09)
, Sept. 14–18,
2009
,
Rome, Italy
.
You do not currently have access to this content.