In model tests with low Reynolds numbers (Re), wall-mounted elements are used for promoting boundary layer transition, which aims to imitate the turbulent flow around the full-scale subjects with high Reynolds numbers. Ship model test results are obtained for model-scale ship flow for Re of 105 to 106, and these results are extrapolated to full-scale ship flow for Re of 108–109. However, only global measurement data have been used to enforce a brute force approach, ignoring relaminarization, overstimulation, and parasitic drag in local flow features. To address these problems, the freestream velocity within the boundary layer around the wall-mounted elements was investigated in this study. Different size two-dimensional (2D) cylindrical rods and various configurations of an array of three-dimensional (3D) cylinders were considered. The effects of wall-mounted elements were analyzed based on the roughness Reynolds number and spanwise wavenumber, calculated based on the height in the wall normal direction and the spacing between the 3D cylinders, respectively. The range of roughness Reynolds number for promoting a transition to turbulence without overstimulation was identified as 30–118 for 2D cylindrical rods and 262–1268 for arrays of 3D cylinders.

1.
Abdelaziz
,
M.
,
Djenidi
,
L.
,
Ghayesh
,
M. H.
, and
Chin
,
R.
, “
Influence of skewed three-dimensional sinusoidal surface roughness on turbulent boundary layers
,”
Phys. Fluids
35
(
5
),
055143
(
2023
).
2.
American Society of Mechanical Engineers (ASME)
,
Test Uncertainty. The American Society of Mechanical Engineers Performance Test Code, 19.1
(
ASME
,
2005
).
3.
Andersson
,
P.
,
Berggren
,
M.
, and
Henningson
,
D. S.
, “
Optimal disturbances and bypass transition in boundary layers
,”
Phys. Fluids
11
(
1
),
134
150
(
1999
).
4.
Andersson
,
P.
,
Brandt
,
L.
,
Bottaro
,
A.
, and
Henningson
,
D. S.
, “
On the breakdown of boundary layer streaks
,”
J. Fluid Mech.
428
,
29
60
(
2001
).
5.
Clauser
,
F. H.
, “
The turbulent boundary layer
,”
Adv. Appl. Mech.
4
,
1
51
(
1956
).
6.
Cossu
,
C.
and
Brandt
,
L.
, “
Stabilization of Tollmien–Schlichting waves by finite amplitude optimal streaks in the Blasius boundary layer
,”
Phys. Fluids
14
(
8
),
L57
L60
(
2002
).
7.
Dobre
,
M.
and
Bolle
,
L.
, “
Practical design of ultrasonic spray devices: Experimental testing of several atomizer geometries
,”
Exp. Therm. Fluid Sci.
26
,
205
211
(
2002
).
8.
Ergin
,
F. G.
and
White
,
E. B.
, “
Unsteady and transitional flows behind roughness elements
,”
AIAA J.
44
(
11
),
2504
2514
(
2006
).
9.
Fransson
,
J. H.
,
Brandt
,
L.
,
Talamelli
,
A.
, and
Cossu
,
C.
, “
Experimental and theoretical investigation of the nonmodal growth of steady streaks in a flat plate boundary layer
,”
Phys. Fluids
16
(
10
),
3627
3638
(
2004
).
10.
Hanson
,
R. E.
,
Buckley
,
H. P.
, and
Lavoie
,
P.
, “
Aerodynamic optimization of the flat-plate leading edge for experimental studies of laminar and transitional boundary layers
,”
Exp. Fluids
53
(
4
),
863
871
(
2012
).
11.
Huber
,
A. F.
and
Mueller
,
T. J.
, “
The effect of trip wire roughness on the performance of the Wortmann FX 63–137 airfoil at low Reynolds numbers
,”
Exp. Fluids
5
(
4
),
263
272
(
1987
).
12.
Jain
,
I.
and
Sarkar
,
S.
, “
Exploring flow transition induced by surface-mounted riblets using large eddy simulations
,”
Phys. Fluids
36
,
024107
(
2024
).
13.
Kendall
,
A.
and
Koochesfahani
,
M.
, “
A method for estimating wall friction in turbulent wall-bounded flows
,”
Exp. Fluids
44
(
5
),
773
780
(
2008
).
14.
Kuester
,
M. S.
and
White
,
E. B.
, “
Roughness receptivity and shielding in a flat plate boundary layer
,”
J. Fluid Mech.
777
,
430
460
(
2015
).
15.
Lee
,
S. B.
,
Seok
,
W.
, and
Rhee
,
S. H.
, “
Computational simulations of transitional flows around turbulence stimulators at low speeds
,”
Int. J. Naval Archit. Ocean Eng.
13
,
236
245
(
2021
).
16.
Luchini
,
P.
, “
Reynolds-number-independent instability of the boundary layer over a flat surface: Optimal perturbations
,”
J. Fluid Mech.
404
,
289
309
(
2000
).
17.
Marusic
,
I.
,
Chauhan
,
K. A.
,
Kulandaivelu
,
V.
, and
Hutchins
,
N.
, “
Evolution of zero-pressure-gradient boundary layers from different tripping conditions
,”
J. Fluid Mech.
783
,
379
411
(
2015
).
18.
Michelsen
,
F. C.
,
Couch
,
R. B.
, and
Kim
,
H. C.
,
Resistance and Propulsion Tests on Two Series 60 Models
(
The University of Michigan
,
1961
).
19.
Musker
,
A. J.
, “
Explicit expression for the smooth wall velocity distribution in a turbulent boundary layer
,”
AIAA J.
17
(
6
),
655
657
(
1979
).
20.
Park
,
D. W.
and
Lee
,
S. B.
, “
The sensitivity of ship resistance to wall-adjacent grids and near-wall treatments
,”
Int. J. Naval Archit. Ocean Eng.
10
(
6
),
683
691
(
2018
).
21.
Park
,
J.
and
Rhee
,
S. H.
, “
Experimental investigation of the transition by a turbulence stimulator in a flat plate boundary layer
,” to be presented at the
35th Symposium on Naval Hydrodynamics
, Nantes, France (
2024
) (unpublished conference paper).
22.
Pattenden
,
R. J.
,
Turnock
,
S. R.
, and
Zhang
,
X.
, “
Measurements of the flow over a low-aspect-ratio cylinder mounted on a ground plane
,”
Exp. Fluids
39
,
10
21
(
2005
).
23.
Purtell
,
L. P.
,
Klebanoff
,
P. S.
, and
Buckley
,
F. T.
, “
Turbulent boundary layer at low Reynolds number
,”
Phys. Fluids
24
(
5
),
802
811
(
1981
).
24.
Schneider
,
S. P.
, “
Effects of roughness on hypersonic boundary-layer transition
,”
J. Spacecr. Rockets
45
(
2
),
193
209
(
2008
).
25.
Silvestri
,
A.
,
Ghanadi
,
F.
,
Arjomandi
,
M.
,
Cazzolato
,
B.
, and
Zander
,
A.
, “
The application of different tripping techniques to determine the characteristics of the turbulent boundary layer over a flat plate
,”
ASME J. Fluids Eng.
140
(
1
),
011204
(
2018
).
26.
Smith
,
A. M. O.
and
Clutter
,
D. W.
, “
The smallest height of roughness capable of affecting boundary-layer transition
,”
J. Aerosp. Sci.
26
(
4
),
229
245
(
1959
).
27.
Spalding
,
D. B.
, “
A single formula for the law of the wall
,”
J. Appl. Mech.
28
(
3
),
455
458
(
1961
).
28.
Tani
,
I.
, “
Boundary-layer transition
,”
Annu. Rev. Fluid Mech.
1
(
1
),
169
196
(
1969
).
29.
Tumin
,
A.
and
Reshotko
,
E.
, “
Spatial theory of optimal disturbances in boundary layers
,”
Phys. Fluids
13
(
7
),
2097
2104
(
2001
).
30.
Williams
,
O. J.
,
Sahoo
,
D.
,
Baumgartner
,
M. L.
, and
Smits
,
A. J.
, “
Experiments on the structure and scaling of hypersonic turbulent boundary layers
,”
J. Fluid Mech.
834
,
237
270
(
2018
).
31.
Zhang
,
D.
,
Cheng
,
L.
,
An
,
H.
, and
Zhao
,
M.
, “
Direct numerical simulation of flow around a surface-mounted finite square cylinder at low Reynolds numbers
,”
Phys. Fluids
29
(
4
),
045101
(
2017
).
You do not currently have access to this content.