This paper provides detailed measurements of the flow in a ribbed coolant passage, and attempts to delineate the important mechanisms that contribute to the production of turbulent shear stress and the normal stresses. It is shown that the separated flow behind the rib is dictated by large-scale structures, and that the dynamics of the large-scale structures, associated with sweep, ejection, and inward and outward interactions, all play an important role in the production of the turbulent shear stress. Unlike the turbulent boundary layer, in a separated shear flow past the rib, the inward and outward interaction terms are both important, accounting for a negative stress production that is nearly half of the positive stress produced by the ejection and sweep mechanisms. It is further shown that the shear layer wake persists well past the re-attachment location of the shear layer, implying that the flow between ribbed passages never recovers to that of a turbulent boundary layer. Therefore, even past re-attachment, the use of statistical turbulence models that ignore coherent structure dynamics is inappropriate.

1.
P. K. Panigrahi and S. Acharya, “Spectral characteristics of separated flow behind a surface mounted square rib,” AIAA Paper No. 96-1931, 1996.
2.
Acharya
S.
,
Myrum
T. A.
, and
Inamdar
S.
, “
Subharmonic excitation of the shear layer between two ribs: vortex interaction and pressure field
,”
AIAA Journal
, Vol.
29
, No.
9:
1390
1399
,
1991
.
3.
R. A. Antonia and R. E. Luxton, “The response of a turbulent boundary layer to an upstanding step change in surface roughness,” ASME Journal of Fluids Engineering, pp. 22–34, 1971.
4.
Tropea
C. D.
and
Gackstatter
R.
, “
The flow over two-dimensional surface-mounted obstacles at low Reynolds number
,”
ASME Journal of Fluids Engineering
,
107
:
489
494
,
1985
.
5.
Liou
T. M.
and
Kao
C. F.
, “
Symmetric and asymmetric turbulent flows in a rectangular duct with a pair of ribs
,”
ASME Journal of Fluids Engineering
,
110
:
373
379
,
1988
.
6.
Myrum
T. A.
,
Qiu
X.
, and
Acharya
S.
, “
Heat transfer enhancement in a ribbed duct using vortex generators
,”
Int. J. Heat Mass Transfer
,
36
, No.
14
:
3497
3508
,
1993
.
7.
Wallace
J. M.
,
Eckelmann
H.
, and
Brodkey
R. S.
, “
The wall region in turbulent shear flow
,”
J. Fluid Mech.
,
54
:
39
48
,
1972
.
8.
Acharya
S.
,
Dutta
S.
,
Myrum
T. A.
, and
Baker
R. S.
, “
Turbulent flow past a surface mounted two-dimensional rib
,”
ASME Journal of Fluids Engineering
, Vol.
116
, pp.
238
246
,
1994
.
9.
Hasan
M. A. Z.
, “
The flow over a backward facing step under controlled perturbation: Laminar separation
,”
J. Fluid Mech.
,
238
:
73
96
,
1992
.
10.
M. Arnal and R. Friedrich, “The instantaneous structure of a turbulent flow over a back-ward facing step,” Separated Flows and Jets, IUTAM Symposium Novosibirsk/USSR, pp. 709–717, 1991.
11.
Corino
E. R.
and
Brodkey
R. S.
, “
A visual study of turbulent shear flow
,”
J. Fluid Mech.
,
37
,
1
1
,
1969
.
12.
Willmarth
W. W.
and
Lu
S. S.
, “
Structure of the reynolds stress near the wall
,”
J. Fluid Mech.
,
55
, Part 1:
65
92
,
1972
.
13.
Bogard
D. G.
and
Tiederman
W. G.
, “
Burst detection with single-point velocity measurements
,”
J. Fluid Mech.
,
162
:
389
413
,
1986
.
14.
Bogard
D. G.
and
Tiederman
W. G.
, “
Characteristics of ejections in turbulent channel flow
,”
J. Fluid Mech.
,
179
:
1
19
,
1987
.
15.
Luchik
T. S.
and
Tiederman
W. G.
, “
Timescale and structure of ejections and bursts in turbulent channel flows
,”
J. Fluid Mech.
,
174
:
529
552
,
1987
.
16.
Stetler
L. D.
and
Stock
D. E.
, “
On the bursting frequency in wind-generated fully rough turbulent boundary layer flows
,”
Turbulent Flows
, FED-Vol.
188
:
25
30
,
1994
.
17.
Volino
R. J.
and
Simon
T. W.
, “
An application of octant analysis to turbulent and transitional flow data
,”
ASME JOURNAL OF TURBOMACHINERY
,
116
:
752
758
,
1994
.
18.
V. De Brederode and P. Bradshaw, “Three dimensional flow in nominally two-dimensional separation bubbles: Flow behind a rearward-facing step,” Imperial College of Science and Technology, England, Dept. of Aeronautics. Rept No. 72-19, 1972.
19.
Roos
F. W.
and
Kagelman
J. T.
, “
Control of coherent structures in reattaching laminar and turbulent shear layers
,”
AIAA Journal
,
24
, No.
12
:
1956
1963
,
1986
.
20.
D. M. Driver and H. L. Seegmiller, “Features of a reattaching turbulent shear layer subject to an adverse pressure gradient,” Paper No. AIAA-82-1029, 1982.
21.
J. K. Eaton and J. P. Johnston, “Low frequency unsteadyness of a reattaching turbulent shear layer,” Proc. Third International Symposium on Turbulent Shear Flows, Davis, CA, pp. 162–170, 1981.
22.
Bhattacharjee
S.
,
Scheelke
B.
, and
Troutt
T. R.
, “
Modification of vortex interactions in a reattaching separated flow
,”
AIAA Journal
,
24
, No.
4
:
623
629
,
1986
.
This content is only available via PDF.
You do not currently have access to this content.